HERITAGE BANCORP

Reno, Nevada 895021 East Main Street, American Fork, Utah 84003

NOTICE OF SPECIAL MEETING OF SHAREHOLDERS OF

TO BE HELD JULY 11, 2019ALTABANCORP^TM

TO THE SHAREHOLDERS OF HERITAGE BANCORP:[    ], 2021

To the Shareholders of Altabancorp:

A special meeting of the shareholders of Heritage BancorpAltabancorp (“Heritage”AB”) will be held on July 11, 2019, at 9:00 a.m. Pacific Daylight Time, at 2330 South Virginia Street, Reno, Nevada.[___], 2021. The special meeting will be held in a virtual meeting format only. Please visit the website www.proxydocs.com/ALTAand enter your control number to register to attend the meeting. The deadline to register to attend the virtual special meeting is [__], 2021, at 5:00 p.m. Mountain Time. You are encouraged to vote your shares by telephone, by completing and mailing the enclosed form of proxy, or online in advance of the special meeting but may also vote during the meeting by following the instructions available on the meeting website. The special meeting will convene at [___] Mountain Time for the following purposes:

Holders of record of HeritageAB common stockshares at the close of business on May 24, 2019,[___], 2021, the record date for the special meeting, are entitled to notice of and to vote at the special meeting or any adjournments or postponements of it. The affirmative vote of the holders of at least a majority of the outstanding shares of Heritage’s outstandingAB’s common stock entitled to vote is required for approval of the merger agreement. To that end, Heritage’sAB’s directors and executive officers and acertain significant shareholdershareholders have signed agreements to vote their shares in favor of the merger agreement. SuchAs of the record date, such persons arewere entitled to vote 843,828[_________] shares representing approximately 61.6%[____]% of all outstanding shares of HeritageAB common stock.shares. As of May 24, 2019,the record date, there were 1,368,319[__________] AB common shares of Heritage common stock outstanding.

Your vote is important. Whether or not you plan to attendparticipate in the special meeting please complete, sign, datevirtually, we encourage you to submit a proxy to vote your shares as promptly as possible in order to make certain that you are represented at the meeting. You may submit a proxy over the Internet, as well as by telephone or by completing, signing, dating and promptly returnreturning the accompanying proxy using the enclosed envelope. If for any reason you should desire to revoke your proxy, you may do so at any time before it is voted at the meeting.If you do not vote your shares, it will have the same effect as voting against the merger.

The board of directors of HeritageAB has determined that the merger agreement is fair to, advisable, and in the best interests of HeritageAB and its shareholders and unanimously recommends that you vote FOR approval of the merger agreement.agreement, FOR approval of the merger-related named executive officer compensation proposal, and FOR approval of the adjournment proposal. With regard to its recommendation that shareholders vote FOR approval of the merger agreement, the board of directors of HeritageAB considered a number of factors, as discussed in “ Background“Background of and Reasons for the Merger” beginning on page 20.26. Such factors also constituted the reasons that the board of directors determined to approve the merger agreement and to recommend that HeritageAB shareholders vote in favor of the merger agreement.

You will receive instructions on howImportant Notice Regarding the Availability of Proxy Materials for the

Special Shareholders Meeting to exchange your sharesbe held [____] 2021:

The proxy statement and notice of Heritage common stock for the merger consideration promptly after the closing of the merger.special meeting are available at www.proxydocs.com/ALTA or from our Investor Relations website at www.altabancorp.com.

Reno, Nevada

June 4, 2019

provided on the Glacier and AB websites is not part of this proxy statement/prospectus and is not incorporated herein by reference. Copies of the documents that Glacier or AB, respectively, files with the SEC can also be obtained, free of charge, by directing a written request to Glacier Bancorp, Inc., 49 Commons Loop, Kalispell, Montana 59901, ATTN: Corporate Secretary or to Altabancorp, 1 East Main Street, American Fork, Utah 84003, ATTN: Corporate Secretary.

Glacier has filed a registration statement on Form S-4 to register with the SEC Glacier common shares as specified therein. This proxy statement/prospectus is a part of that registration statement. As permitted by SEC rules, this document does not contain all of the information included in the registration statement or in the exhibits or schedules to the registration statement. You may read and copy the registration statement, including any amendments, schedules and exhibits, at the addresses set forth below. Statements contained in this document as to the contents of any contract or other documents referred to in this document are not necessarily complete. In each case, you should refer to the copy of the applicable contract or other document filed as an exhibit to the registration statement. This document incorporates important business and financial information about Glacier fromand AB that is not included in or delivered with this document, including incorporating by reference documents that Glacier hasand AB have previously filed with the SecuritiesSEC. These documents contain important information about the companies and Exchange Commission (“SEC”) and that are contained in or incorporated by reference into this proxy statement/prospectus. For a listing of Glacier documents incorporated by reference into this proxy statement/prospectus, please see the section entitledtheir financial condition. See “Where You Can Find More Information.” This information isThese documents are available for you to review at the SEC’s website athttp://www.sec.gov.

You may request copies of this proxy statement/prospectus and any of the documents incorporated by reference into this proxy statement/prospectus or other information concerning Glacier, without charge byto you upon written or oral request to the applicable company’s principal executive offices. The respective addresses and telephone or writtennumbers of such principal executive offices are listed below:

To obtain timely delivery of these documents, you must request directed to:

Glacier Bancorp, Inc.

49 Commons Loop

Kalispell, Montana 59901

ATTN: Ron Copher, Corporate Secretary

Telephone: (406)751-7706

Certain reports can also be found on Glacier’s website atwww.glacierbancorp.com.

Glacier’s common stock is traded on the NASDAQ Global Select Market under the symbol “GBCI.”

You will not be charged for the documents that you request. If you would like to request documents, please do so by July 3, 2019information no later than [    ], 2021, in order to receive them before the Heritage special shareholders’ meeting.meeting of AB shareholders (the “AB special meeting”).

Heritage

Heritage does not have a class of securities registeredGlacier common shares, par value $0.01 per share, are traded on the Nasdaq Global Select Market, under Section 12 of the Securities Exchange Act of 1934 (the “Exchange Act”), is not subject tosymbol “GBCI,” and AB common shares, par value $0.01 per share, are traded on The Nasdaq Capital Market under the reporting requirements of Section 13(a) or 15(d) of the Exchange Act, and accordingly does not file documents or reports with the SEC.

If you have questions concerning the merger or this proxy statement/prospectus, would like additional copies of this proxy statement/prospectus, would like copies of Heritage’s articles of incorporation or bylaws, or would like copies of Heritage’s historical consolidated financial statements or need help voting your shares, please contact:

Heritage Bancorp

2330 South Virginia Street

Reno, Nevada 89502

ATTN: Stanley Wilmoth, President and Chief Executive Officer

(775)321-4110symbol “ALTA.”

TABLE OF CONTENTS

Appendix A – Plan and Agreement of Merger, dated as of May 18, 2021

i

QUESTIONS AND ANSWERS

Why am I receiving these materials?

We are sending you these materials to solicit your proxy to vote in favor of the merger and to help you decide how to vote your shares of Heritage BancorpAltabancorp (“Heritage”AB”) common stock with respect to its proposed merger with Glacier Bancorp, Inc. (“Glacier”). The merger cannot be completed unless HeritageAB receives the affirmative vote of the holders of at least a majority of the outstanding shares of Heritage’sAB’s common stock. Heritagestock entitled to vote on the matter. AB is holding a special meeting of shareholders to vote on proposals relating to the merger. Information about the special meeting is contained in this document. See “Heritage“AB Special Shareholders Meeting.”

This document is both a proxy statement of HeritageAB and a prospectus of Glacier. It is a proxy statement because the officers and board of directors of HeritageAB (the “Heritage“AB Board”) are soliciting proxies from HeritageAB’s shareholders in connection with voting on the merger. It is a prospectus because Glacier will issue shares of its common stock in exchange for AB common shares of Heritage common stock as a portion of the consideration to be paid in the merger.

What will Heritagehappen in the merger?

In the proposed merger, AB will merge with and into Glacier, with Glacier surviving the merger. Immediately following the merger, Altabank (the “Bank”) will be merged into Glacier’s subsidiary Glacier Bank. Shares of Glacier will continue to trade on The Nasdaq Global Select Market, with the trading symbol “GBCI.”

What will AB shareholders receive in the merger?

Under the terms of the merger agreement, each AB common share (including each share to be issued upon settlement of Heritage commoneach unvested restricted stock unit (“RSU”)) will be exchanged for a “unit” comprised of 4.000.7971 shares of Glacier common stock and $12.00 in cash,(the “per share stock consideration”), subject to adjustment as described below.certain adjustments, with cash paid in lieu of fractional shares.

Assuming for purposes of illustration only that the average closing price for Glacier common stock is $40.66$[___] (which was the closing price forof Glacier common stock on May 24, 2019)[___], 2021), each share of HeritageAB common stockshare would be exchanged for 4.000.7971 shares of Glacier common stock with a total value equal to $162.64, in addition to the cash consideration of $12.00 per share.$[___].

The per share stock portion of each unitconsideration may be adjusted in certain circumstances based on whether Glacier common stock is trading either higher or lower than prices specified in the merger agreement immediately prior to the closing of the merger, in order to avoid termination of the merger agreement.

The cash portion of each unitIn addition, the per share stock consideration will be subject to reduction if the “HB“AB Closing Capital”,Capital,” as defined in the merger agreement, is less than the target of $99,117,206,$342,937,000, subject to certain adjustments. In such event, the cash portionnumber of each unitshares of Glacier common stock to be issued will be reduced on a pro rataper-share basis byin accordance with the amount of such deficiency.formula set forth in the merger agreement.

If the HBAB Closing Capital exceeds $99,117,206,$342,937,000, subject to certain adjustments, HeritageAB may, upon written notice to Glacier and effective immediately prior to the closing of the merger, declare and pay a special dividend to its shareholders in the amount of such excess.

By voting to approve the merger agreement, HeritageAB shareholders will give the HeritageAB Board the authority to elect to cause HeritageAB to accept a reduction on aper-share basis of the number of shares of Glacier common stock to be issued in the merger if the Glacier average closing price exceeds $50.59$74.15, as described above.below. See “The Merger – Termination of the Merger Agreement.”

Assuming the exchange of all outstanding HeritageAB common stockshares for Glacier common stock as a portion of the mergerper share stock consideration in accordance with the merger agreement and that none of the outstanding options to purchase Heritage commonper share stock are exercised, Heritageconsideration is not adjusted as

described above, AB shareholders will receive in the aggregate, approximately 5,473,276an estimated 15,129,749 shares of Glacier common stock in the merger, representing approximately 5.9%13.7% of Glacier’s outstanding common stock after taking into account Glacier shares to be issued in the merger.

If the merger does not occur by November 30, 2019,February 28, 2022, either Glacier or HeritageAB may unilaterally terminate the merger agreement, subjectagreement. However, if as of February 28, 2022, all required regulatory approvals have not been obtained, then the deadline for consummation of the merger will be extended to an extensionon or before April 30, 2022, if either Glacier or AB notifies the other party in writing on or prior to February 28, 2022, of its election to extend such date under certain circumstances.date.

When and where will the special meeting take place?

HeritageAB will hold a special meeting of its shareholders on July 11, 2019,[___], 2021, at 9:[___] Mountain Time. The special meeting will be held in virtual meeting format only. In order to attend the special meeting, AB shareholders must register at www.proxydocs.com/ALTA by 5:00 a.m. Pacific Daylightp.m. Mountain Time at 2330 South Virginia Street, Reno, Nevada.on [__], 2021.

Who may vote at the special meeting?

The HeritageAB Board has set May 24, 2019[___], 2021 as the record date for the special meeting. If you were the owner of HeritageAB common stockshares at the close of business on May 24, 2019,[___], 2021, you may vote at the special meeting. Each holder of AB common shares is entitled to one vote for each AB common share owned as of the record date.

What constitutes a quorum for the special meeting?

The quorum requirement for the special meeting is the presence at the meeting or by proxy of a majority of the total number of outstanding AB common shares entitled to vote.

What vote is required to approve the merger agreement?

Approval of the merger agreement requires the affirmative vote of the holders of at least a majority of the outstanding shares of Heritage’s outstandingAB’s common stock.stock entitled to vote on the matter. As described in this proxy statement/prospectus, Heritage’sAB’s directors and executive officers and acertain significant shareholdershareholders have agreed to vote the shares they are entitled to vote in favor of the merger agreement. As of the record date, hereof, such persons arewere entitled to vote 843,828[_________] AB common shares, of Heritage common stock, representing approximately 61.6%[___]% of all outstanding shares of HeritageAB common stock. Accordingly, shareholder approval of the merger agreement is assured.shares. See “Heritage“AB Special Shareholders’ Meeting” and “The Merger – Voting Agreement.Agreements.”

You may cast your vote by submitting a proxy through the Internet or by telephone by following the instructions included on the enclosed proxy card or by mail by completing, signing and dating the enclosed proxy card and returning it to us promptly in the enclosed envelope. ReturningSubmitting a proxy through the Internet or by telephone or returning the proxy card will not affect your right to attend the special meeting by virtual means and vote.

If you choose to vote your shares at the virtual special meeting, you should follow the instructions available on the shareholder meeting website.

If your shares are registered in person“street name” in the name of a broker or other nominee and you wish to vote at the special meeting, please bringyou will need to obtain a legal proxy from your bank or brokerage firm. Please consult the enclosedvoting form sent to you by your bank or broker to determine how to obtain a legal proxy in order to vote at the meeting.

What if I fail to submit a proxy or to instruct my broker, bank or other nominee?

If you fail to properly submit a proxy or to instruct your broker, bank or other nominee to vote your AB common shares, and you do not attend the special meeting and vote your shares, your shares will not be voted. This will have the same effect as a vote “AGAINST” approval of the merger agreement, but will have no impact on the outcome of the other proposals.

Can I attend the special meeting and vote my shares at the meeting?

Yes. Although the AB Board requests that you submit a proxy through the Internet, by telephone or by returning the proxy card and proofaccompanying this proxy statement/prospectus, all shareholders are invited to attend the shareholder meeting. Shareholders of identification.record on [__________], 2021 can vote at the special meeting by following the instructions available on the meeting website.

Can I change my vote after I have mailedsubmitted my signed proxy card?proxy?

Yes. YouIf you do not hold your shares in “street name,” there are three ways you may change your vote at any time after you have submitted your proxy and before your proxy is voted at the special meeting. If your shares of Heritage common stock are held in your own name, you may change your vote as follows:meeting:

If you choose either the first or second method above, you must submit youra written notice of revocation, or your new proxy card to Heritage’sit must be received by AB’s Secretary prior to the vote at the special meeting. If you grant a new proxy by telephone or Internet, your revised instructions must be received by 11:59 p.m., Mountain Time, one day before the meeting date.

If you have instructed a bank, broker or other nominee to vote your shares, you must follow the directions you receive from your bank, broker or other nominee to change your voting instructions.

What happens if I return my proxy but do not indicate how to vote my shares?

If you sign and return your proxy card but do not provide instructions on how to vote your shares of HeritageAB common stockshares at the special meeting of shareholders, your shares of HeritageAB common stockshares will be voted “FOR” approval ofthe proposal to approve the merger agreement, “FOR” the merger-related named executive compensation proposal and “FOR” approval of one or more adjournments of the special meeting.

If my shares are held in “street name” by my broker, bank or other nominee, will my broker, bank or other nominee automatically vote my shares for me?

No. Your broker, bank or other nominee will not vote your shares unless you provide instructions to your broker, bank or other nominee on how to vote. You should instruct your broker, bank or other nominee to vote your shares by following the instructions provided by the broker, bank or nominee with this proxy statement/prospectus.

How does the HeritageAB Board recommend that I vote?

The HeritageAB Board unanimously recommends that HeritageAB shareholders vote “FOR” the proposals described in this proxy statement/prospectus, including in favor of approval of the merger agreement.agreement and the merger-related named executive compensation proposal.

What do I need to do now?

We encourage you to read this proxy statement/prospectus and related information in its entirety. Important information is presented in greater detail elsewhere in this document, and documents governing the merger are attached as appendices to this proxy statement/prospectus. In addition, much of the business and financial information about Glacier that may be important to you is incorporated by reference into this document from documents separately filed by Glacier with the Securities and Exchange Commission (“SEC”). This means that important disclosure obligations to you are satisfied by referring you to one or more documents separately filed with the SEC.

Following review of this proxy statement/prospectus,please complete, sign,submit a proxy through the Internet, by telephone or by completing, signing, and datedating the enclosed proxy card and return it in the enclosed envelopeas soon as possible so that your shares of HeritageAB common stockshares can be voted at Heritage’sAB’s special meeting of shareholders.

What happens if I sell my shares after the record date but before the special meeting?

The record date of the special meeting is earlier than the date of the special meeting and the date that the merger is expected to be completed. If you sell or otherwise transfer your shares after the record date, but before the date of the special meeting, you will retain your right to vote at the special meeting, but you will not have the right to receive the merger consideration to be received by shareholders in the merger. In order to receive the merger consideration, a shareholder must hold his or her shares through completion of the merger.

What do I do if I receive more than one proxy statement/prospectus or set of voting instructions?

If you hold shares directly as a record holder and also in “street name” or otherwise through a nominee, you may receive more than one proxy statement/prospectus and/or set of voting instructions relating to the special meeting. These should each be voted and/or returned separately in order to ensure that all of your shares are voted.

Should I send in my common stock certificates now?

No.Please do not send your HeritageAB common stockshare certificates with your proxy card. You will receive written instructions from Glacier’s exchange agent promptly following the closing of the merger on how to exchange your HeritageAB common stockshare certificates for the merger consideration.

What risks should I consider?consider in deciding whether to vote for approval of the merger agreement?

You should review carefully our discussion under “Risk Factors.” You should also review the factors considered by the HeritageAB Board in approving the merger agreement. See “Background of and Reasons for the Merger.”

What are the material United States federal income tax consequences of the merger to HeritageAB shareholders?

Glacier and Heritage expect to reportAB intend for the merger of Heritage with and into Glacierto qualify as atax-free reorganization for U.S. federal income tax purposes under “reorganization” within the meaning of Section 368(a) of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). It is a condition to the closing ofIf the merger that each party receives an opinion from its respective legal counsel that the merger will qualifyqualifies as a reorganization underwithin the meaning of Section 368(a).

In atax-free reorganization, a shareholder who exchanges his, her or its shares of common stock in an acquired company for shares of common stock in an acquiring company, plus cash, must generally recognize gain (but not loss) on the exchange in an amount equal to the lesser of (1) the amount of gain realized (i.e., the excess of the sumInternal Revenue Code, then for U.S. federal income tax purposes a U.S. holder of the fair market value of theAB common shares of the acquiring company(as defined below) generally will not recognize any gain or loss upon surrendering its AB common stock (including any fractional shares) andshares, except with respect to any cash received pursuant toor treated as received in the merger (excludingand any cash received in lieu of fractional shares) over the shareholder’s adjusted tax basisshares. A U.S. holder of AB common shares receiving cash in his, her or its shareslieu of acquired companya fractional share of Glacier common stock surrendered pursuantwill generally recognize gain or loss equal to the merger), or (2)difference between the amount of cash (excluding any cash received instead of a fractional share and the basis in lieuits fractional share of fractional shares) received pursuantGlacier common stock. The U.S. federal income tax consequences described above may not apply to all holders of AB common shares. Your tax consequences will depend on your individual situation. Accordingly, we strongly urge you to consult an independent tax advisor for a full understanding of the merger.

RISK FACTORS

In addition to the other information contained in or incorporated by reference into this document, including the matters addressed under the caption “Cautionary Note Regarding Forward-Looking Statements,” you should consider the matters described below carefully in determining whether or not to approve the merger agreement and the transactions contemplated by the merger agreement.

Risks Associated with the Proposed Merger

Because you are receiving a fixed number of shares (subject to adjustment) and the market price of the Glacier common stock may fluctuate, you cannot be sure of the value of the shares of Glacier common stock that you will receive.

At the time of the HeritageAB special shareholder meeting, and prior to the closing of the merger, you will not be able to determine the value of the Glacier common stock that you will receive upon completion of the merger. Any change in the market price of Glacier common stock prior to completion of the merger will affect the value of the consideration that HeritageAB shareholders will receive in the merger. Common stock price changes may result from a variety of factors, including but not limited to general market and economic conditions, changes in Glacier’s business, operations and prospects, and regulatory considerations. Many of these factors are beyond the control of Glacier or Heritage.AB. You should obtain current market prices for Glacier common stock.

The merger agreement provides that the number of shares of Glacier common stock to be issued for each share of HeritageAB common stockshare in the merger may be decreased or increased, as the case may be, if the average closing price of Glacier common stock, determined pursuant to the merger agreement, is greater than or less than specified prices. If Glacier’s average closing price determined in accordance with the merger agreement is greater than $50.59$74.15 and Glacier elects to terminate the merger agreement, the HeritageAB Board wouldcould determine, without resoliciting the vote of HeritageAB shareholders, whether or not to accept a decrease on aper-share basis in the number of shares of Glacier common stock to be issued in the merger to avoid such termination. See “The Merger – Termination of the Merger Agreement.”

The results of operations of Glacier after the merger may be affected by factors different from those currently affecting the results of operations of AB.

The businesses of Glacier and AB differ in certain respects and, accordingly, the results of operations of the combined company and the market price of the combined company’s common shares may be affected by factors different from those currently affecting the independent results of operations of AB and Glacier. For a discussion of the business of Glacier and certain factors to be considered in connection with Glacier’s business, see “Information Concerning Glacier” and the documents incorporated by reference in this document and referred to under “Where You Can Find More Information.” For a discussion of the business of AB and certain factors to be considered in connection with AB’s business, see “Information Concerning Altabancorp” and the documents incorporated by reference in this document and referred to under “Where You Can Find More Information.”

The merger agreement limits Heritage’sAB’s ability to pursue other transactions and provides for the payment of abreak-up fee if HeritageAB does so.

While the merger agreement is in effect, subject to very narrow exceptions, HeritageAB and its directors, officers, employees, agents and representatives are prohibited from initiating or encouraging inquiries with respect to alternative acquisition proposals. The prohibition limits Heritage’sAB’s ability to seek offers from other potential acquirers that may be superior from a financial point of view to the proposed transaction. If HeritageAB receives an unsolicited proposal from a third party that is superior from a financial point of view to that made by Glacier and the merger agreement is terminated, HeritageAB will be required to pay a $10,000,000$35,000,000 break-up fee. This fee makes it less likely that a third party will make an alternative acquisition proposal. See “The Merger –Break-Up Fee.”

Combining ourthe two companies may be more challenging, costly or time-consuming than we expect.expected.

Glacier and HeritageAB have operated and, until the completion of the merger, will continue to operate, independently. Although Glacier has successfully completed numerous mergers in the recent past, this is a larger transaction than others and regardless it is possible that the integration of Heritagethe Bank into Glacier Bank could result in the loss of key employees, the disruption of the ongoing business of Heritagethe Bank or inconsistencies in standards, controls, procedures and policies that adversely affect ourthe Bank’s ability to maintain relationships with customers and employees or to achieve the anticipated benefits of the merger. As with any merger of banking institutions, there also may be disruptions that cause usthe Bank to lose customers or cause customers to take their deposits out of Heritagethe Bank.

Glacier has provisions in its articles of incorporation that could impede a takeover of Glacier.

Glacier’s articles contain provisions providing for, among other things, preferred stock and super majority shareholder approval of certain business combinations. Although these provisions were not adopted for the express purpose of preventing or impeding the takeover of Glacier without the approval of Glacier’s board of directors, they may have that effect. Such provisions may prevent you from taking part in a transaction in which you could realize a premium over the current market price of Glacier common stock. See “Comparison of Certain Rights of Holders of Glacier and Heritage Common Stock” for a description of Glacier’s potential takeover provisions.

After the merger is completed, HeritageAB shareholders will become Glacier shareholders and will have different rights that may be less advantageous than their current rights.

Upon completion of the merger, HeritageAB shareholders will become Glacier shareholders. Differences in Heritage’sAB’s articles and Heritage’sAB’s bylaws and Glacier’s articles and Glacier’s bylaws will result in changes to the rights of HeritageAB shareholders who become Glacier shareholders. See “Comparison of Certain Rights of Holders of Glacier and HeritageAB Common Stock.Shares.”

Heritage’sAB’s shareholders will have a reduced ownership and voting interest after the merger and will exercise less influence over management.

Heritage’sAB’s shareholders currently have the right to vote in the election of the Heritage board of directorsAB Board and on other significant matters affecting Heritage,AB, such as the proposed merger with Glacier. When the merger occurs, each HeritageAB shareholder will become a shareholder of Glacier with a percentage ownership of the combined organization that is much smaller than the shareholder’s percentage ownership of Heritage.AB. Based on the anticipated number of Glacier common shares to be issued in the merger, it is anticipated that the HeritageAB shareholders will only own approximately 5.9%13.7% of all of the outstanding shares of Glacier’s common stock following the merger. Because of this, Heritage’sAB’s shareholders will have less influence on the management and policies of Glacier than they now have on the management and policies of Heritage.AB. Furthermore, shareholders of Glacier do not have preemptive or similar rights, and therefore, Glacier can sell additional voting securities in the future without offering them to the former HeritageAB shareholders, which would further reduce their ownership percentage in, and voting control over, Glacier.

The merger may fail to qualify as a reorganization for federal tax purposes, resulting in the recognition by Heritage’sAB’s shareholders of taxable gain or loss in respect of their HeritageAB shares.

Glacier and HeritageAB intend the merger to qualify as a reorganization within the meaning of Section 368(a) of the Internal Revenue Code. Although the Internal Revenue Service will not provide a ruling on the matter, Glacier and Heritage,AB, as a condition to closing, will each obtain an opinion from their respective legal counsel that the merger will qualify as a reorganization for federal tax purposes. These opinions do not bind the Internal Revenue Service or the courts or prevent either from taking a contrary position. Neither Glacier nor AB has requested and neither intends to request any ruling from the Internal Revenue Service from adopting a contrary position. If the merger fails to qualify as a reorganization, a Heritage shareholder generally would recognize gain or loss in an amount equal to the difference between (1) the sumU.S. federal income tax consequences of the amount of cash and the aggregate fair market value of the Glacier common stock received in the exchange, and (2) the Heritage shareholder’s aggregate adjusted tax basis in the Heritage common stock surrendered in the exchange.merger. Furthermore, if the merger fails to qualify as a reorganization, Glacier, as successor to Heritage,AB, may incur a significant tax liability since the merger would be treated as a taxable sale of Heritage’sAB’s assets for U.S. federal income tax purposes.

Glacier and AB will be subject to business uncertainties and contractual restrictions while the merger is pending.

Uncertainty about the effect of the merger on employees, customers and vendors may have an adverse influence on the business, financial condition and results of operations of Glacier and AB. These uncertainties may impair Glacier’s and AB���s ability to attract, retain and motivate key personnel, maintain current deposit levels, and continue to attract depositors and attract new borrowers pending the consummation of the merger, as such personnel, depositors and borrowers may experience uncertainty about their future relationships following the consummation of the merger. Additionally, these uncertainties could cause customers (including depositors and borrowers), suppliers, vendors and others who deal with Glacier or AB to seek to change existing business relationships with Glacier, AB or the combined company or fail to extend an existing relationship with Glacier, AB or the combined company.

In addition, the merger agreement restricts AB from taking certain actions without Glacier’s consent while the merger is pending. These restrictions could have a material adverse effect on AB’s business, financial condition and results of operations. See “The Merger Agreement — Covenants” for a description of the restrictive covenants applicable to AB.

Failure to complete the merger could negatively impact the stock prices and future businesses and financial results of Glacier and AB.

If the merger is not completed, the ongoing businesses of Glacier and AB may be adversely affected, and Glacier and AB will be subject to several risks, including the following:

In addition, if the merger is not completed, Glacier and/or AB may experience negative reactions from the financial markets and from their respective customers and employees. Glacier and/or AB also could be subject to litigation related to any failure to complete the merger or to enforcement proceedings commenced against Glacier or AB to perform their respective obligations under the merger agreement. If the merger is not completed, Glacier and AB cannot assure their respective shareholders that the risks described above will not materialize and will not materially affect the business, financial results and stock prices of Glacier and/or AB.

The merger is subject to the receipt of approvals and/or waivers or non-objections from governmental authorities that may delay the date of completion of the merger or impose conditions that could have an adverse effect on Glacier.

Before the merger may be completed, various approvals, waivers or non-objections must be obtained from state and federal governmental authorities, including the Federal Deposit Insurance Corporation, the Board of Governors of the Federal Reserve System, the Commissioner of the Montana Division of Banking and Financial Institutions, and the Utah Department of Financial Institutions. Satisfying the requirements of these governmental authorities may delay the date of completion of the merger. In addition, these governmental authorities may include conditions on the completion of the merger, or require changes to the terms of the merger. While Glacier and AB do not currently expect that any such conditions or changes would result in a material adverse effect on Glacier, there can be no assurance that they will not, and such conditions or changes could have the effect of delaying completion of the merger, or imposing additional costs on or limiting the revenues of Glacier following the merger, any of which might have a material adverse effect on Glacier following the merger. The parties are not obligated to complete the merger should any required regulatory approval, waiver or non-objection contain a condition or requirement not normally imposed in such transactions that would deprive Glacier of the economic or business benefits of the merger in a manner that is material relative to the aggregate economic business benefits of the merger to Glacier, subject to certain rights granted in the merger agreement to appeal any denial of such regulatory approval.

Risks Associated with AB’s Business

AB is, and will continue to be, subject to the risks described in AB’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020, as updated by its Quarterly Report on Form 10-Q for the quarter ended March 31, 2021, and subsequent Current Reports on Form 8-K, and Quarterly Reports on Form 10-Q, all of which are filed with the SEC and incorporated by reference into this proxy statement/prospectus. See “References to Additional Information” and “Where You Can Find More Information” included elsewhere in this proxy statement/prospectus.

Risks Associated with Glacier’s Business

Glacier is, and will continue to be, subject to the risks described in Glacier’s Annual Report on Form10-K for the fiscal year ended December 31, 2018,2020, as updated by its Quarterly Report on Form 10-Q for the quarter ended March 31, 2021, and subsequent Current Reports on Form8-K, and Quarterly Reports on Form 10-Q, all of which are filed with the SEC and incorporated by reference into this proxy statement/prospectus. See “References to Additional Information” and “Where You Can Find More Information” included elsewhere in this proxy statement/prospectus.

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This document, including information included or incorporated by reference in this document may contain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to,to: (i) statements about the benefits of the merger, including future financial and operating results, cost savings, enhancements to revenue and accretion to reported earnings that may be realized from the merger;(ii) statements about our respectiveGlacier’s and AB’s plans, objectives, expectations, intentions, projected financial information, future opportunities and intentions andany other statements regarding Glacier’s and AB’s future expectations, beliefs, plans, objectives, results of operations, financial condition and cash flows that are not historical facts; (iii) the expected timetable for completing the merger; (iv) the ability to complete the merger; and(iii) (v) other statements identified by words such as “expects,” “anticipates,” “intends,” “plans,” “believes,” “seeks,” “estimates,” or words of similar meaning. These forward-looking statements are based on current beliefs and expectations of Glacier’s and AB’s management and are inherently subject to significant business, economic and competitive uncertainties and contingencies, many of which are beyond Glacier’s and Heritage’sAB’s control. In addition, these forward-looking statements are subject to assumptions with respect to future business strategies and decisions that are subject to change.

In addition to factors previously disclosed in Glacier’s and AB’s reports filed with the SEC relating to risks to Glacier’s and AB’s business and stock price, and those identified elsewhere in this document (including the section entitled “Risk Factors”), the following potential factors, among others, could cause actual results to differ materially from the anticipated results or other expectations expressed or implied in the forward-looking statements:

The foregoing list of factors is not intended to be exhaustive. These forward-looking statements reflect Glacier’s and AB’s current views with respect to future events and are based on numerous assumptions and assessments made by Glacier and AB in light of their experiences and perceptions of historical trends, current conditions, business strategies, operating environments, future developments and other factors they believe appropriate. By their nature, forward-looking statements involve known and unknown risks and uncertainties because they relate to events and depend on circumstances that will occur in the future. The factors described in the context of such forward-looking statements in this document could cause Glacier’s and AB’s plans with respect to the merger, actual results, performance or achievements, industry results and developments to differ materially from those expressed in or implied by such forward-looking statements. Although it is believed that the expectations reflected in such forward-looking statements are reasonable, no assurance can be given that such expectations will prove to have been correct and persons reading this document are therefore cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this proxy statement/prospectus or, in the case of a document incorporated by reference, as of the date of that document. All subsequent written and oral forward-looking statements concerning the proposed transaction or other matters attributable to Glacier or HeritageAB or any person acting on behalf of Glacier or HeritageAB are expressly qualified in their entirety by the cautionary statements above. Neither Glacier nor HeritageAB undertakes any obligation to update any forward-looking statements to reflect circumstances or events that occur after the date the forward-looking statements are made.

SELECTED HISTORICAL FINANCIAL INFORMATION OF GLACIER

The following table presents selected consolidated financial information of Glacier for the periods and dates indicated. This information has been derived from Glacier’s consolidated financial statements filed with the SEC. Historical data as of and for the three months ended March 31, 2019 and 2018 are based upon unaudited financial statements and include, in the opinion of Glacier management, all normal recurring adjustments considered necessary to present fairly the results of operations and financial condition of Glacier. The consolidated financial data below should be read in conjunction with the consolidated financial statements and notes thereto, incorporated by reference in this proxy statement/prospectus. See “Where You Can Find More Information.”

HERITAGEAB SPECIAL SHAREHOLDERS’ MEETING

Date, Time, Place

The HeritageAB special meeting of shareholders will be held on July 11, 2019,[___], 2021, at 9:[___] Mountain Time. The special meeting will be held in virtual meeting format only. In order to attend the special meeting, AB shareholders must register at www.proxydocs.com/ALTA by 5:00 a.m. Pacific Daylightp.m. Mountain Time at 2330 South Virginia Street, Reno, Nevada.on [__], 2021.

As described below under the “Votes Required and Quorum,” approval of the merger agreement requires the affirmative vote of at least a majority of the outstanding shares of Heritage’s outstandingAB’s common stock.stock entitled to vote on the matter. The proposal to approve merger-related compensation to named executives on an advisory basis will be approved if the votes cast in favor of the proposal exceed the votes cast opposing the proposal, assuming a quorum is present. The proposal to adjourn the special meeting, if necessary or appropriate, including adjournments to solicit additional proxies, will be approved if the votes cast in favor of the proposal exceed the votes cast againstopposing the proposal, assumingwhether or not a quorum is present.

Purpose

At the special meeting, HeritageAB shareholders will:

Record Date; Shares Outstanding and Entitled to Vote

The HeritageAB Board has fixed the close of business on May 24, 2019[___], 2021, as the record date for determining the holders of shares of HeritageAB common stockshares entitled to notice of and to vote at the special meeting. At the close of business on the record date, there were approximately 361[___] holders of record and 1,368,319[___] AB common shares of Heritage common stock issued and outstanding. Holders of record of HeritageAB common stockshares on the record date are entitled to one vote per shareshare. Unvested RSUs do not have voting rights.

AB’s directors and are also entitled to exercise dissenters’ rights if certain procedures are followed. See “The Merger – Dissenters’ Rights” andAppendix B.

Heritage’s directors, executive officers and acertain significant shareholdershareholders have agreed to vote all shares of HeritageAB common stockshares they are entitled to vote that are held or controlled by them in favor of approval of the merger agreement. As of the record date, hereof, a total of 843,828[_________] AB common shares, of Heritage common stock, representing approximately 61.6%[____]% of all outstanding AB common shares of Heritage common stock, are covered by thesubject to voting agreement.agreements. See “The Merger – Interests of Heritage Directors and Executive Officers in the Merger – Voting Agreement.”Agreements”.

Votes Required and Quorum

The affirmative vote of the holders of at least a majority of the outstanding shares of Heritage’s outstandingAB’s common stock entitled to vote is required to approve the merger agreement. At least a majority of the total outstanding AB common shares of Heritage common stockentitled to vote must be present, either in personat the meeting or by proxy, in order to constitute a quorum for the special meeting. For purposes of determining a quorum, abstentions areand broker non-votes will be counted in determining the shares present at a meeting.

With respect to the merger-related named executive compensation proposal, approval of such proposal requires that the votes cast in favor of the proposal exceed the votes cast opposing the proposal. As a result, abstentions and broker non-votes with respect to the merger-related named executive officer compensation proposal will have no effect on the merger-related named executive officer compensation proposal.

With respect to the proposal to adjourn the special meeting if necessary or appropriate, if a quorum is not present at the special meeting, shareholders entitled to vote at the special meeting, present at the meeting or by proxy, will have the power to adjourn the special meeting. If a quorum is present at the special meeting, the proposal to adjourn the special meeting, if necessary or appropriate, including an adjournment to solicit additional proxies in favor of the merger agreement, will be approved if the votes cast in favor of the proposal exceed the votes cast opposing the proposal.

Voting, Solicitation, and Revocation of Proxies

If you are a holder of record of AB common shares as of the record date for the special meeting, there are four ways to have your shares voted:

If the enclosed proxy card is duly executed and received in time for the special meeting, it will be voted in accordance with the instructions given. If the proxy card is duly executed and received but no instructions are given, it is the intention of the persons named in the proxy to vote the shares represented by the proxyFOR the approval of the merger agreement, FOR the proposal to approve merger-related compensation of AB’s named executive officers andFOR the proposal to approve one or more adjournments to solicit additional proxies, and in the proxy holder’s discretion on any other matter properly coming before the meeting. Any proxy given by a shareholder may be revoked before its exercise by:

HeritageAB is soliciting the proxy for the special meeting on behalf of the HeritageAB Board. HeritageAB will bear the cost of solicitation of proxies from its shareholders. In addition to using the mail, HeritageAB may solicit proxies by personal interview, telephone, and facsimile. Banks, brokerage houses, other institutions, nominees, and fiduciaries will be requested to forward their proxy soliciting material to their principals and obtain authorization for the execution of proxies. Heritage does not expect to pay any compensation for the solicitation of proxies. However, HeritageAB will, upon request, pay the standard charges and expenses of banks, brokerage houses, other institutions, nominees, and fiduciaries for forwarding proxy materials to and obtaining proxies from their principals.

Voting in Person at the Special Meeting

Shares helddirectly in your name as the shareholder of record may be voted in person atduring the special meeting. If you choose to vote your shares of Heritage common stock in person, please bringmeeting by following the enclosed proxy card or proof of identification.instructions available on the meeting website. Even if you plan to attendparticipate at the virtual special

meeting, we recommendAB recommends that you vote your shares of HeritageAB common stockshares in advance as described above so that your vote will be counted if you later decide not to attend the special meeting.

If your shares are registered in “street name” in the name of a broker or other nominee and you wish to vote during the special meeting, you will need to obtain a legal proxy from your bank or brokerage firm. Please consult the voting form sent to you by your bank or broker to determine how to obtain a legal proxy in order to vote at the meeting.

The AB Proposals

Proposal 1: Merger Proposal

AB is asking its shareholders to approve the merger agreement. For a detailed discussion of the terms and conditions of the merger agreement, please see the section entitled “The Merger.” AB shareholders should read this proxy statement/prospectus, including any documents incorporated in this proxy statement/prospectus by reference, and its annexes, carefully and in their entirety for more detailed information concerning the merger agreement and the merger. A copy of the merger agreement is attached to this proxy statement/prospectus as Appendix A.

As discussed in the section entitled “Background of and Reasons for the Merger,” after careful consideration, the AB Board approved the execution, delivery and performance of the merger agreement and the transactions contemplated by it, including the merger, and determined the merger to be fair and in the best interests of AB and the AB shareholders.

Required Vote

Approval of the proposal to approve the merger agreement requires the affirmative vote of at least a majority of the outstanding shares of AB’s common stock entitled to vote. If you mark “ABSTAIN” on your proxy card, fail to submit a proxy card or fail to vote by mail, by telephone, via the Internet, or via remote participation through the virtual format of the meeting at the AB special meeting, or are a “street name” holder and fail to instruct your bank, broker, or other nominee how to vote, it will have the same effect as votes against the merger proposal.

The approval of the merger by holders of AB common shares is a condition to the completion of the merger.

The AB Board recommends that AB shareholders vote “FOR” the proposal to approve the merger agreement.

Proposal 2: Advisory Proposal to Approve Merger-Related Named Executive Officer Compensation

Pursuant to Section 14A of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), AB is providing its shareholders with the opportunity to cast an advisory (non-binding) vote to approve the compensation that may be paid or become payable to its named executive officers that is based on or otherwise relates to the merger, as disclosed in the section entitled “The Merger—Interests of AB Directors and Executive Officers in the Merger.” As required by Section 14A of the Exchange Act, AB is asking its shareholders to vote to adopt the following resolution:

“RESOLVED, that the compensation that may be paid or become payable to AB’s named executive officers that is based on or otherwise relates to the merger, and the agreements or understandings pursuant to which such compensation may be paid or become payable, in each case as disclosed pursuant to Item 402(t) of Regulation S-K in the section of the proxy statement/prospectus statement entitled “The Merger—Merger-Related Compensation for AB’s Named Executive Officers”, are hereby APPROVED.”

Required Vote

Approval of the advisory proposal to approve merger-related named executive officer compensation requires that the number of votes cast in favor of the proposal exceed the votes cast opposing the proposal,

assuming a quorum is present. If you mark “ABSTAIN” on your proxy card, fail to submit a proxy card or fail to vote by mail, by telephone, via the Internet, or via remote participation through the virtual format of the meeting at the AB special meeting, or are a “street name” holder and fail to instruct your bank, broker, or other nominee how to vote, it will have no effect on the merger-related named executive officer compensation proposal.

The vote to approve the merger-related named executive officer compensation proposal is a vote separate and apart from the vote to approve the merger agreement. Accordingly, a shareholder may vote to approve the merger-related named executive officer compensation proposal and vote not to approve the merger agreement or vice versa. Because the merger-related named executive officer compensation proposal vote is advisory only, it will not be binding on the parties to the merger. If the merger is completed, the merger-related named executive officer compensation subject to the merger-related named executive officer compensation proposal will be paid to AB’s named executive officers to the extent payable in accordance with the terms of the applicable compensation agreements and arrangements even if holders of AB common shares fail to approve the merger-related named executive officer compensation proposal.

The approval of the merger-related named executive officer compensation proposal is not a condition to the completion of the merger.

The AB Board recommends a vote “FOR” the proposal to approve merger-related compensation of AB’s named executive officers.

Proposal 3: Adjournment Proposal

AB is asking its shareholders to approve the adjournment of the AB special meeting to another date and place if necessary or appropriate to solicit additional votes in favor of the merger proposal if there are insufficient votes at the time of such adjournment to approve the merger proposal.

If, at the AB special meeting, an insufficient number of AB common shares are present via remote participation through the virtual format of the meeting or represented by proxy and voting in favor of the merger proposal, AB will move to adjourn the AB special meeting to enable the AB Board to solicit additional proxies for approval of the merger proposal. If the AB shareholders approve the adjournment proposal, AB may adjourn the AB special meeting and use the additional time to solicit additional proxies, including the solicitation of proxies from AB shareholders who have previously voted. If the date of the adjournment is not announced at the AB special meeting or a new record date is fixed for the adjourned meeting, a new notice of the adjourned meeting will be given to each shareholder of record entitled to vote at the adjourned meeting.

Required Vote

Approval of the adjournment proposal requires that the number of votes cast in favor of the proposal exceed the votes cast opposing the proposal, whether or not a quorum is present. If you mark “ABSTAIN” on your proxy card, fail to submit a proxy card or fail to vote by mail, by telephone, via the Internet, or via remote participation through the virtual format of the meeting at the AB special meeting, or are a “street name” holder and fail to instruct your bank, broker, or other nominee how to vote, it will have no effect on the adjournment proposal.

The AB Board recommends that AB shareholders vote “FOR” the adjournment proposal.

Other Matters to Come Before the AB Special Meeting

As of the date of this proxy statement/prospectus, the AB Board is not aware of any matters that will be presented for consideration at the AB special meeting other than as described in this proxy statement/prospectus. If, however, the AB Board properly brings any other matters before the AB special meeting, the persons named in the proxy will vote the shares represented thereby in accordance with the recommendation of the AB Board on any such matter.

BACKGROUND OF AND REASONS FOR THE MERGER

Background of the Merger

As partThe AB Board, with the assistance of its ongoing considerationexecutive management, periodically reviews, assesses, and evaluation of Heritage’s long-term prospectsdiscusses AB’s strategic direction, performance, and strategy, Heritage’s Board of Directorsprospects. These reviews and senior managementdiscussions have periodically reviewedincluded from time to time, third party advisors, including investment bankers and assessedexternal legal counsel, and have addressed the potential strategic alternatives that might be available to AB, including organic growth opportunities, and challenges. The Board of Directors has considered the prospects of continued growth and operating a financial institution under current economic, regulatory and competitive conditions. At the same time, like many other smaller financial institutions, Heritage has experienced increasing costs related to technology and regulatory compliance.

As part of the Board of Directors’ and management’s evaluation of ways to meet these challenges, they have met regularly with Davidson to review developments in the banking industry and the equity markets generally, thepotential mergers and acquisitions (including potential acquisition targets and the sale of AB), and capital planning decisions, all with the goal of enhancing shareholder value. These reviews and discussions have also included analyses of the business environment for financial institutions, including technology initiatives and investments, the impact of low interest rates, the evolution of community banking, and talent acquisition and retention. Economic outlook nationally and locally, the regulatory and compliance environment, financial institution industry trends, peer comparisons, ongoing consolidation among financial institutions, and the benefits and risks of continued operation as a standalone company have also been considered. Factors assessed in connection with these reviews have included the risks and opportunities associated with operating in existing and new markets, competition, potential positive and negative expense and revenue synergies, regulatory requirements, interest rate environment and prospects, scale, operational risk, credit risk, market Heritage’s financial performance relativerisk, and changes in technology and in delivery and marketing channels. In connection with the evaluation of strategic alternatives, AB’s executive management has had, from time to certaintime, informal discussions, including regarding potential acquisitions or the sale of AB, with representatives of other financial institutions capital management strategies (for example, stock repurchases and dividends) and valuation trends. Davidson is a nationally recognized investment banking firm with substantial experience advising financial institutions generally, including with respect to mergers and acquisitions.has regularly updated the AB Board regarding such discussions.

Representatives of Heritage and Glacier had held informational discussions in prior years. On May 8, 2018, members of management of Glacier met with Heritage’s Chairman of the Board, Robert Cashell, and itsRandall M. Chesler, President and Chief Executive Officer Stanley Wilmoth,of Glacier, and Len E. Williams, President and Chief Executive Officer of AB, have lengthy careers in the financial institutions industry and have known each other professionally for the last two to three years since Mr. Williams joined AB. Messrs. Chesler and Williams have periodically informally discussed matters of mutual interest to their respective institutions, and Mr. Chesler inquired on at Davidson’s annual financial institutions’ group conference. The parties discussed general banking matters.least one occasion about a potential business combination.

Certain members of the Gunther family and their related entities (the “Section 13D Group”) executed a shareholder agreement on January 28, 2020 and jointly filed a Schedule 13D with the Securities & Exchange Commission on June 12, 2020. At a meeting on May 22, 2018, the Heritagetime, two of the 10 members of the AB Board met with Davidson aswere part of the Board’s ongoing assessmentSection 13D Group.

To avoid potential conflicts of Heritage’sinterest and to advance the best interests of the company and its shareholders, in July of 2020, all 10 members of the AB Board unanimously voted to establish a special committee comprising all directors other than the directors that were members of the Section 13D Group to act on behalf of the company with respect to considering and responding to the goals and requests of the Section 13D Group.

In August 2020, the AB Board convened its regularly scheduled annual two-day retreat to review, assess, and set the company’s strategic opportunitiesdirection. As is customary practice, the AB Board, with the assistance of executive management, considered and challenges. Representativesset various key strategic objectives for the company. In addition, the AB Board and executive management considered and discussed the contents and potential impacts of Heritage’s special counsel, Luse Gorman, PC (“Luse Gorman”) also attended the meeting. AtSchedule 13D filing by the meeting, Luse Gorman reviewed strategic planning guidelinesSection 13D Group. After considering the positive performance trajectory of the company, the successful implementation of technology initiatives, and an overviewthe experience and capabilities of director responsibilitiesexecutive management, among other factors, the AB Board adopted and conduct duringendorsed the strategic planning process,direction for the company, including to remain independent and pursue organic growth and potential acquisition opportunities.

In November 2020, executive management presented an opportunity to acquire a bank outside of the state of Utah. The AB Board reviewedunanimously directed executive management to begin formal discussions with Party X regarding a potential acquisition.

During the course of the next several months, at regularly-scheduled Board meetings and discussed with Luse Gorman the Board’s fiduciary duties in a merger context. Davidson then discussedthrough periodic communications with the AB Board, developments inexecutive management provided the banking industry, an updateAB Board updates on the equity markets as well as valuations for peer financial institutions and other financial institutions in general, the mergers and acquisition market and current valuation metrics. Davidson reviewed the merger and acquisition process and other merger considerations, including a list of potential strategic partners for Heritage, which such list included Glacier. The Board then discussed engaging Davidson to render financial advisory and investment banking services to Heritage in connection with analyzing Heritage’s strategic alternatives. Following this discussion, the Board of Directors approved the engagement of Davidson and the initiation of a process for the identification and evaluation of potential strategic alternatives for Heritage.

On September 6 and 7, 2018, members of management of a publicly traded bank holding company (“Company A”), which was one of the companies identified by Davidson as a potential acquiror for Heritage, met with Messrs. Cashell and Wilmoth. The parties discussed various items, including mergers and acquisitions in general, as well as Company A’s interest in pursuing a merger transaction in the Nevada market. Messrs. Cashell and Wilmoth reported the results of this discussion to the full Board of Directors.

From April through October 2018, Davidson conducted due diligence on Heritage, and Davidson and Heritage prepared a package of confidential information that could be shared with interested parties.

On October 2 and 3, 2018, Messrs. Wilmoth and Cashell met with members of management of Glacier at Glacier’s offices. The parties discussed various items, including Glacier’s operations of its banking divisions and Heritage’s operations. Messrs. Cashell and Wilmoth reported the results of this discussion to the full Board of Directors.unsolicited

contacts and inquiries from third parties regarding a possible sale of the company, including unsolicited approaches from Glacier and Party B, key metrics on the company’s strategic direction adopted at the AB Board’s annual retreat, and progress on various potential acquisition opportunities.

On January 11, 2021, the AB Board unanimously approved the submission of a non-binding letter of interest to Party X regarding the acquisition of Party X by AB.

On January 15, 2021, Paul Gunther, a member of the Section 13D Group, resigned as a director of AB.

At a special meeting convened on January 15, 2021, the AB Board considered and discussed the strategic objectives of the company. Mr. Williams also provided an update to the AB Board on potential acquisition opportunities. In addition, the AB Board considered and discussed the amended Schedule 13D filed by the Section 13D Group on January 14, 2021, which included a letter to the AB Board requesting that the AB Board review strategic alternatives for AB, including a potential sale of the company. The filing also noted the 13D Group’s objection to AB acquiring another bank and its concern that the current Board of Directors and executive management would be incapable of successfully executing such a transaction. Keefe, Bruyette & Woods, Inc., acting as financial advisor to AB (“KBW”), was invited to the meeting to discuss with the AB Board the potential process for undertaking a review of the company’s strategic alternatives and how KBW could assist in that review.

At its regularly-scheduled meeting on October 16, 2018,January 26, 2021, the HeritageAB Board againreceived a presentation from Jones Day, legal counsel to AB, regarding the directors’ fiduciary duties under applicable law and related obligations in reviewing and considering strategic alternatives, which was followed by review and discussion with KBW of strategic considerations and the following alternatives: (i) remain standalone/independent; (ii) pursue mergers and acquisitions; (iii) explore a merger of equals; or (iv) undertake a controlled sale process. The market landscape, potential targets, prospective buyers, valuation considerations, and related financial considerations were reviewed and discussed. The AB Board met with representatives of Davidson and Luse Gorman. Thein executive session to discuss the foregoing, after which the AB Board again reviewed strategic planning guidelines and an overview of director responsibilities and conduct duringvoted unanimously to continue with the strategic planning process,direction previously agreed to in August 2020 at the AB Board’s annual retreat, mainly to remain as an independent entity and pursue potential acquisition opportunities, including the potential acquisition of Party X.

On January 27, 2021, the Section 13D Group filed an amended Schedule 13D, which included a letter to the AB Board, reiterating the Section 13D Group’s request that AB review strategic alternatives, including a discussionpotential sale of the Board’s fiduciary dutiescompany.

On February 1, 2021, Jonathan Gunther, a member of the Section 13D Group, resigned as a director of AB.

At a special meeting convened on February 11, 2021, The AB Board considered recent developments, including the ongoing consolidation among financial institutions, executive management’s ongoing discussions regarding a potential acquisition opportunity, and the significant potential costs likely to be incurred by AB and the potential disruption to AB’s business in the event of a proxy contest. The AB Board discussed the company’s strategic alternatives in light of these developments and how best to further validate the best future strategy for AB. The AB Board determined to direct KBW to (i) approach prospective buyers to solicit interest in a merger context. Davidson then updatedpossible sale of the previous discussion regarding developments in the banking industry, the equity marketscompany and valuations for financial institutions, the mergers and acquisition market and current valuation metrics. Davidson reviewed an updated list of 11 potential priority partners for Heritage, which list included Glacier, and further discussed the merger and acquisition process and other merger considerations, including a preview of information that would be providedalso (ii) to potential partners on a confidential basis. The 11 potential priority partners that were discussed were identified due to their desirable franchises and operations as well as their higher probability of interest or previously expressed interest in Heritage. The Board then agreed toconcurrently continue to move forward with a potential acquisition of Party X.

At the direction of the AB Board, on February 16, 2021 executive management, with the assistance of KBW, commenced the solicitation process for a possible sale of AB. Continuing over the course of several days, representatives of KBW contacted or were contacted by potential counterparties, including Glacier. With KBW’s assistance, the AB Board and directedexecutive management Davidson and legal counsel to proceed further with preparing Heritage for, and to conduct, a solicitation process targeted at the 11 identified potential partners,buyers of AB with (i) the greatest financial ability to pay (based on their relative buying power versus third parties, as determined based on publicly available information) and directed management to update(ii) a similar strategic direction and adviseculture as AB. Each of the Board as tonine potential

counterparties received initial marketing information and draft non-disclosure agreements. Ultimately, seven of those parties expressed interest in the progresspotential acquisition of such process at regularly scheduled Board meetings.

Following this meeting, Davidson contacted all 11 potential partners concerning their level of interest, if any, in a possible business combination with Heritage. Heritage’s identity was not disclosed to these parties at that time. Four of these parties, including Glacier, indicated a preliminary interest. HeritageAB, executed customary non-disclosure agreements, with all four of these potential merger partners, after which those parties were informed of Heritage’s identity. On November 17, 2018,received preliminary due diligence information, and received a virtual data room containing a confidential information memorandum and additional information about Heritage was opened and access was granted to each of these four parties after they executed thenon-disclosure agreements.

On December 3, 2018, Davidson provided a request for proposal to the four interested parties, asking thatprocess letter requesting indications of interest be submittedby March 12, 2021. Of the parties that executed a non-disclosure agreement, four parties elected to receive a management presentation and meeting.

At its regularly-scheduled meeting on or before December 13, 2018.February 24, 2021, the AB Board received an update from KBW regarding the sale process, including preliminary due diligence performed by interested counterparties, and the anticipated timeline for indications of interest, as well as an update from executive management on the company’s concurrent pursuit of a potential acquisition of Party X.

During the period from March 2, 2021 to March 5, 2021, AB conducted management presentations and meetings with Glacier, Party A, Party B, and Party C.

On December 5, 2018,March 8, 2021, Glacier’s executive management team and D.A. Davidson & Co., financial advisor to Glacier (“D.A. Davidson”), met with the Glacier board of directors to discuss the pro forma financial modeling and approach to submitting a letter of intent later in the week. D.A. Davidson also discussed pricing strategies based on other interested banks’ ability to pay, as well as Glacier’s pricing differentiation versus the other banks needed to encourage AB to conclude the process in one round and move forward with Glacier.

At a special meeting convened on March 15, 2021, KBW reviewed with the AB Board the process undertaken to date by AB, with KBW’s assistance, in respect of a potential sale of the four interested parties met with Heritage’s management. Representatives of Davidson attended the meeting.

On December 11, 2018, one of the four interested parties, a publicly traded bank holding company (“Company B”) met with Heritage’s management. Representatives of Davidson attended the meeting.

On December 13, 2018, Glacier submitted an indicationcompany. AB received indications of interest that proposed paying merger considerationto acquire AB from (i) Glacier indicating an all-stock proposal (with the potential for a special cash dividend based on the amount of $192.18 per Heritage share, payable in 3.9AB capital and certain other amounts at closing) at a fixed exchange ratio of 0.7971 shares of Glacier common stock (valued at $43.99for each AB common share, which (excluding any special cash dividend) represented an implied per share asvalue of December 12, 2018) and $12.00 in cash, plus additional cash based upon Heritage’s earnings between December 31, 2018 and the closing of the transaction.

On December 13, 2018, Company A submitted an indication of interest that proposed the terms of an acquisition of Heritage, payable 100% in Company A stock. On December 13, 2018, management held a preliminary discussion with Davidson, after which Davidson contacted Glacier’s representatives in an effort to get Glacier to increase its proposed merger consideration.

On December 14, 2018, Company B submitted an indication of interest that proposed the terms of an acquisition of Heritage, payable 100% in Company B stock. The fourth interested party declined to submit an indication of interest.

Also on March 15, 2021, the Section 13D Group filed an amended Schedule 13D, which included a letter to AB’s shareholders, announcing the Section 13D group’s intention to consider a “vote no” campaign against certain of AB’s directors.

KBW informed Glacier of the AB Board’s decision to pursue and negotiate a business combination transaction with Glacier on March 16, 2021. Executive management representatives of Glacier and AB negotiated and discussed additional deal terms within the parameters discussed with the AB Board over the course of the next several business days, including, without limitation, the amount of Glacier’s requested termination fee and the history and recent financial performance and trading metrics of eachduration of the institutions submittingexclusivity period to be granted to Glacier for purposes of negotiating a definitive agreement. On March 18, 2021, the parties executed a letter of intent.

Commencing March 22, 2021 and continuing through May 18, 2021, Messrs. Chesler and Williams and other executive management representatives from Glacier and AB, respectively, had periodic telephonic meetings to discuss and negotiate the terms of the merger and potential integration. During this period, Glacier performed extensive diligence of AB, and AB, in turn, undertook reverse diligence of Glacier during this time period. During the diligence process, various working groups from Glacier and AB, including information technology, accounting, retail operations, legal and compliance, credit, human resources, marketing, internal audit, data warehouse, and commercial banking, met virtually to exchange information and discuss the proposed transaction. Representatives of KBW and D.A. Davidson also attended many of these meetings.

At the regularly-scheduled AB Board meeting on March 31, 2021, Mr. Williams provided the AB Board an indication of interest. After considering all three proposals,update regarding the proposed merger transaction, including the pricing offeredstatus of due diligence and various potential integration matters. The potential negative impact of the recent decline in Glacier’s stock price, as well as the qualityinterest rate effect on the fair valuation of investment securities available for sale and naturethe corresponding recording of the merger consideration being offered and each institution’s history, overall operations, recent financial performance, current trading values, overall operating philosophy and expected strategic fit with Heritage,unrealized gain or loss to shareholders’ equity, on the Board decided that the proposals from Companytransaction’s economics were discussed. A and Company B were financially and strategically less desirable than Glacier’s proposal. The Heritage Board considered Glacier’s intention to create a new Nevada banking division comprised of Heritage’s branches and the expectation that the business structure would limit disruption of Heritage’s business and have a limited impact on Heritage’s employees. The Heritage Board unanimously agreed to accept the indication of interest from Glacier, subject to satisfactory resolution of a few termsspecial meeting of the indicationAB Board was convened on April 1, 2021 to discuss the transaction’s economics further. After consultation with and input from executive management, Jones Day, and KBW, the AB Board directed executive management of interest.the company to move forward with due diligence and KBW and executive management of the company to continue to monitor closely the transaction economics.

Between December 19 and December 26, 2018, Heritage and Glacier, with assistance of their respectiveOn April 16, 2021, Miller Nash LLP, legal counsel and financial advisors, negotiated several aspects of Glacier’s letter of intent. After several discussions and consideration,to Glacier and Heritage signed a nonbinding letter of intent on December 26, 2018, which described the principal merger terms and(“Miller Nash”), provided that Heritage would negotiate with Glacier exclusively for a period of 75 days. Accordingly, Heritage’s discussions with Company A and Company B ceased.

On February 15, 2019, Glacier’s counsel provided Heritage’s counsel with an initial draft of the merger agreement. Glacier, HeritageBetween that receipt date and their respective legal counselMay 14, 2021, Miller Nash and financial advisors conducted due diligence and drafted and negotiatedJones Day exchanged drafts of the merger agreement and related ancillaryother transaction documents, including voting agreements through April 3, 2019.

Beginning March 1, 2019, Heritageto be entered into by each of the directors and Davidson conducted documenteach of the executive officers of AB and certain other shareholders of AB and non-compete/non-solicitation agreements to be entered into by each of the directors. The two law firms and the respective management teams negotiated, exchanged drafts, and worked towards finalizing the terms and conditions of the merger agreement, the voting agreements and other transaction documents. AB negotiated with Glacier to obtain more favorable terms and conditions in the merger agreement. Reciprocal due diligence on Glacier. On March 8, 2019, representativescontinued during this time period as well.

At the April 28, 2021 regularly-scheduled AB Board meeting, Mr. Williams provided the AB Board a detailed update regarding the proposed merger transaction, including the status of due diligence, negotiation of the merger agreement, and various operational and integration matters. With participation from Heritage,Jones Day, the AB Board reviewed and discussed the negotiation of key terms of the draft merger agreement, proposed voting agreements for executive officers and directors, and proposed non-compete/non-solicitation agreements for directors. The AB Board considered the governance structure of Glacier, including its board of directors as well as its divisional board structure. The AB Board discussed a proposed timeline for completing negotiation and anticipated next steps and directed KBW to meet with D.A. Davidson and Glacier participatedregarding the transaction and the impact of the recent decline in Glacier’s stock price, as well as the interest rate effect on the fair valuation of investment securities available for sale and the corresponding recording of the unrealized gain or loss to shareholders’ equity.

On May 10, 2021, a reverse due diligence conference call to provide information to Heritage regardingspecial meeting of the AB Board was convened. KBW updated the AB Board on its discussion with Glacier and answer questions from HeritageD.A. Davidson about the transaction’s economics. Jones Day addressed the status of the legal documentation for the proposed transaction. The proposed timing and Davidson.strategy for approaching the Section 13D Group regarding the proposed transaction was also discussed. The Board discussed the overall strength and viability of the proposed transaction, taking into account the fluctuation in the implied valuation as a result of changes in stock prices, and the AB Board instructed executive management of AB to continue to move forward negotiating the potential transaction with the assistance of AB’s external advisors. The AB Board also authorized executive management and the advisors of AB to contact Davis Partnership, L.P., Davis Capital Partners, LLC and Lansing Davis (collectively, the “Davis Group”) and representatives for the Section 13D Group in connection with the potential transaction.

Also on May 10, 2021, Mr. Williams approached the Davis Group regarding execution of a customary non-disclosure agreement to facilitate discussion about the potential transaction and garnering the group’s support for the same through execution of a voting agreement.

On March 20, 2019,May 11, 2021, the HeritageDavis Group entered into a non-disclosure agreement.

On or about May 11, 2021, as directed by the AB Board, togetherKBW and Jones Day approached the investment banker and legal counsel, respectively, for the Section 13D Group regarding execution of a customary non-disclosure agreement to facilitate discussion about the potential transaction and garnering the group’s support for the same through execution of a voting agreement.

On May 12, 2021, the Section 13D Group entered into a non-disclosure agreement with AB, after which KBW and Jones Day discussed with the Section 13D Group’s advisors the general terms of the proposed transaction and the request for execution of a voting agreement. During the period from May 12, 2021 to May 17, 2021, legal counsel to the Section 13D Group, Miller Nash, Jones Day, and executive management of AB negotiated and exchanged drafts of the voting agreement.

Also on May 12, 2021, Mr. Williams discussed the potential transaction and the voting agreement with the Davis Group. During the period between May 12, 2021 and May 17, 2021, legal counsel to the Davis Group, Miller Nash, Jones Day and management of AB negotiated and exchanged drafts of the voting agreement.

Also on May 12, 2021, certain executive officers of AB were presented with draft employment agreements to be entered into in connection with the signing of the merger agreement. During the period from May 12, 2021 to May 16, 2021, Miller Nash and certain executive officers of AB and their independent counsel negotiated and exchanged drafts of the employment agreements.

On May 17, 2021, at the Section 13D Group’s request, Mr. Chesler, Craig A. Langel, chair of Glacier’s Board of Directors, Ronald J. Copher, Executive Vice President and Chief Financial Officer of Glacier, and Donald J. Chery, Executive Vice President and Chief Administrative Officer of Glacier, met with representatives of Davidson and Luse Gorman, metthe Section 13D Group to discuss the proposed transaction.

Also on May 17, 2021, a special meeting of the AB Board was convened to consider the proposed definitivemerger transaction. Members of executive management and representatives of KBW and Jones Day attended the meeting at the invitation of the AB Board. The AB Board was provided with a set of meeting materials in advance of the meeting, including substantially final drafts of the merger agreement, as negotiated to date. Representatives of Davidson reviewed the financial aspectsvoting agreements which included key members of the proposed merger. Luse Gorman reviewedSection 13D Group and the specificDavis Group, the non-competition/non-solicitation agreements, and a summary of the material terms of the merger agreement prepared by Jones Day. Jones Day discussed with the directors their fiduciary duties under applicable law and reviewed the substantial process involvedaccompanying legal standards. Jones Day proceeded to review in negotiating its terms. The Heritagedetail with the AB Board considered all these matters and determined to continue with negotiations of the proposed merger.

On March 22, 2019, Heritage and Glacier agreed to extend the exclusivity period for negotiations to April 8, 2019.

that, as of thatsuch date and subject to the procedures followed, assumptions made, matters considered, and qualifications and limitations on the review undertaken by Davidson,KBW as set forth in its opinion, the merger considerationexchange ratio in the proposed merger with Glacier was fair, from a financial point of view, to the holders of HeritageAB common stock. Among other mattersshares. The AB Board considered the Heritage Board reviewedvalues of the specificother acquisition proposals that had been previously received, taking into account changes in stock prices, and noted that the consideration in the proposed transaction with Glacier was still clearly the best for shareholders.

After considering the proposed terms of the merger agreement the form and value of the consideration to be received by Heritage shareholders, the price and historical performance of Glacier common stock and related dividend payouts, current market conditions including comparable bank merger and acquisition transactions, the employment of certain Heritage employees following the merger, and the implications of the merger to Heritage’s employees, customers, and communities. After due consideration of these and other matters,transaction documents, and taking into consideration the fairness opinionmatters discussed during that meeting and prior meetings of Davidson, the HeritageAB Board, including the strategic options discussed at those meetings and the factors described under the section of this proxy statement/prospectus entitled “Recommendation of the AB Board and Reasons for the Merger,” the AB Board determined that the merger was fair to and in the best interests of AB and AB shareholders, and the AB Board unanimously approved, entering intoadopted and declared advisable the execution, delivery and performance of the merger agreement and the transactions contemplated by it, including the merger, and recommended to AB’s shareholders that they approve the merger and the merger agreement.

AB executive management then discussed with the AB Board the proposed communication plan, including the public announcement, internal meeting with employees, and schedule for media and investor calls.

On May 18, 2021, a special meeting of the Glacier Board was convened to consider the proposed merger transaction. Members of executive and senior management and representatives of D.A. Davidson and Miller Nash also attended the meeting at the invitation of the Glacier Board. The parties entered intoGlacier Board was provided with a set of meeting materials in advance of the meeting, including substantially final drafts of the merger agreement, on April 3, 2019. After the closevoting agreements, the non-competition/non-solicitation agreements, and a comprehensive due diligence review summary. Miller Nash discussed with the directors their fiduciary duties under applicable law and reviewed the accompanying legal standards. Members of business on April 3, 2019,Glacier’s executive and senior management team then reviewed the parties issuedenhanced due diligence process in detail. This included a joint press release announcingreview of the merger.

Reasons forcredit, compliance and legal findings. D.A. Davidson then reviewed the Merger – Heritage

At a board meeting held on April 3, 2019,financial aspects of the Heritageproposed transaction, including the financial analyses with respect to the proposed transaction that D.A. Davidson performed. Miller Nash proceeded to review in detail with the Glacier Board determined that the terms of the merger agreement, wereincluding the terms of various ancillary documents. After considering the proposed terms of the merger agreement and related transaction documents, and taking into consideration the matters discussed during that meeting and prior meetings of the Glacier Board, the Glacier Board determined that the merger was in the best interests of HeritageGlacier and its shareholders. Glacier shareholders, and the Glacier Board unanimously approved, adopted and declared advisable the execution, delivery and performance of the merger agreement and the transactions contemplated by it, including the merger.

Following receipt of approval of the merger agreement and transaction from the Glacier Board on May 18, 2021, AB and Glacier executed the merger agreement, each of the directors and each of the executive officers of AB, the Davis Group and members of the Section 13D Group executed the voting agreements with Glacier, each of the directors of AB executed the non-solicitation/non-competition agreements with Glacier, and certain executive officers of AB executed their employment agreements with Glacier. On the afternoon of May 18, 2021, each of Glacier and AB issued press releases announcing the execution of the merger agreement.

On May 19, 2021, Glacier and AB each made a customary filing with the SEC on Form 8-K regarding the execution of the merger agreement and included a copy of the merger agreement as an exhibit to such filing.

Recommendation of the AB Board and Reasons for the Merger

After careful consideration, at a meeting held on May 17, 2021, the AB Board determined that the merger agreement, including the merger of the Bank into Glacier Bank, is in the best interests of AB and AB’s shareholders and approved and adopted the merger agreement.

In the course of reaching this determination and relatedits decision to approve the merger agreement, the Heritage Board evaluated the merger and the merger agreement in consultation with the management of Heritage and Heritage’s financial advisor and legal counsel. In reaching its determination, the Heritage Board considered a number of factors. Such factors also constituted the reasons that the Heritage Board determined to approveother transactions contemplated by the merger agreement and to recommend that Heritagethe AB shareholders vote in favor of“FOR” the proposal to approve the merger agreement. Such reasons includedagreement, the following:AB Board evaluated the merger agreement, the merger, and the other transactions contemplated by the merger agreement in consultation with AB’s executive management, as well as AB’s financial advisor, KBW, and legal advisor, Jones Day, and considered various factors, including, without limitation, the following material factors:

The foregoing discussion of the reasons that ledinformation and factors considered by the HeritageAB Board to approve the merger agreement and recommend that Heritage’s shareholders vote in favor of the merger agreement is not intended to be exhaustive, but, is believedrather, includes the material factors considered by the AB Board. In reaching its decision to include allapprove the merger agreement, the merger of the material reasons forBank into Glacier Bank and the Heritage Board’s decision. In reachingother transactions contemplated by the merger agreement, the AB Board did not quantify or assign any relative weights to the factors considered, and individual directors may have given different weights to different factors. The AB Board considered all these factors as a whole and overall considered the factors to be favorable to, and support, its determination to approve and recommend the transaction, the Heritage Board based its recommendation on the totalitymerger agreement.

It should be noted that this explanation of the AB Board’s reasoning and all other information presented to itin this section is forward-looking in nature and, did not assign any relative or specific weights totherefore, should be read in light of the reasons considered in reaching that determination. Individual directors may have given differing weights to different reasons. After deliberating with respect tofactors discussed under the merger with Glacier, considering, among other things, the matters discussed above, the Heritage Board unanimously approved the merger agreement and the merger with Glacier as being in the best interests of Heritage and its shareholders.heading “Cautionary Statement Regarding Forward-Looking Statements.”

Opinion of Heritage’sAB’s Financial Advisor

On May 31, 2018, Heritage entered into an engagement agreement with DavidsonAB engaged KBW to render financial advisory and investment banking services to Heritage. As part of its engagement, Davidson agreedAB, including an opinion to assist Heritage in analyzing, structuring, negotiating and, if appropriate, effecting a transaction between Heritage and another corporation or business entity. Davidson also agreed to provide Heritage’s board of directors with an opinionthe AB Board as to the fairness, from a financial point of view, to the common shareholders of AB of the considerationexchange ratio (referred to be paid toelsewhere in this proxy statement/prospectus as the holders of Heritage’s commonper share stock consideration) in the proposed merger. Heritage engaged DavidsonAB selected KBW because DavidsonKBW is a nationally recognized investment banking firm with substantial experience in transactions similar to the merger and is familiar with Heritage and its business.merger. As part of its investment banking business, DavidsonKBW is continually engaged in the valuation of financial institutionsservices businesses and their securities in connection with mergers and acquisitions and other corporate transactions.acquisitions.

On April 3, 2019,As part of its engagement, representatives of KBW attended the Heritage boardmeeting of directorsthe AB Board held a meeting to evaluateon May 17, 2021, at which the AB Board evaluated the proposed merger.transaction. At this meeting, DavidsonKBW reviewed the financial aspects of the proposed merger and rendered to the AB Board an opinion to the Heritage boardeffect that, as of such date and based upon and subject to the procedures followed, assumptions made, procedures followed, matters considered, and qualifications and limitations on the review undertaken by KBW as set forth in its opinion, the consideration to be paid toexchange ratio in the holders of the Heritage’s common stockproposed merger was fair, from a financial point of view, to suchthe holders of Heritage’sAB common stock inshares. The AB Board directors approved the proposed merger.merger agreement at this meeting.

The full text of Davidson’s written opinion, dated April 3, 2019, is attached asAppendix C to this proxy statement/prospectus and is incorporated herein by reference. The description of the opinion set forth herein is qualified in its entirety by reference to the full text of such opinion. Heritage’s shareholders are urged to read the opinion, which is attached as Appendix B to this document and is incorporated herein by reference, and describes the procedures followed, assumptions made, matters considered, and qualifications and limitations on the review undertaken by KBW in its entirety.preparing the opinion.

Davidson’sKBW’s opinion speaks only as of the date of the opinion and Davidson undertakes no obligation to revise or update its opinion. The opinion iswas for the information of, and was directed to, the Heritage boardAB Board (in its capacity as such) in connection with its consideration of directors and addressesthe financial terms of the merger. The opinion addressed only the fairness, from a financial point of view, of the consideration to be paidexchange ratio in the merger to the holders of Heritage’sAB common stock in the proposed merger. The opinion doesshares. It did not address and Davidson expresses no view or opinion with respect to, (i) the underlying business decision of HeritageAB to engage in the merger (ii) the relative merits or effect ofenter into the merger as comparedagreement or constitute a recommendation to the AB Board in connection with the merger, and it does not constitute a recommendation to any alternative business transactionsholder of AB common shares or strategies that may be or may have been available to or contemplated by Heritage or Heritage’s boardany shareholder of directors, or (iii) any legal, regulatory, accounting, tax or similar matters relating to Heritage, its shareholders or relating to or arising out of the merger. The opinion expresses no view or opinionother entity as to any terms or other aspects ofhow to vote in connection with the merger except for the merger consideration. Heritage and Glacier determined the consideration through the negotiation process. The opinion does not express any view as to the amount or nature of the compensation to any of Heritage’s or Glacier’s officers, directors or employees, or any class ofother matter, nor does it constitute a recommendation regarding whether or not any such persons, relative to the merger consideration,shareholder should enter into a voting, shareholders’ or affiliates’ agreement with respect to the fairness ofmerger or exercise any dissenters’ or appraisal rights that may be available to such compensation. Theshareholder.

KBW’s opinion has beenwas reviewed and approved by Davidson’sKBW’s Fairness Opinion Committee in conformity with its policies and procedures established under the requirements of Rule 5150 of the Financial Industry Regulatory Authority.

Davidson has reviewed the registration statement on FormS-4 of which this proxy statement/prospectus is a part and consented to the inclusion of its opinion to the Heritage board of directors as to this proxy statement/prospectus and to the references to Davidson and its opinion contained herein. A copy of the consent of Davidson is attached as Exhibit 99.2 to the registration statement on FormS-4.

In connection with rendering itsthe opinion, DavidsonKBW reviewed, analyzed and relied upon material bearing upon the financial and operating condition of AB and Glacier and bearing upon the merger, including, among other things, the following:things:

KBW’s consideration of financial information and other factors that it deemed appropriate under the years ending December 31, 2021, December 31, 2022, December 31, 2023,circumstances or relevant to its analyses included, among others, the following:

KBW also performed such other financial studies and analyses as it considered appropriate and investigationstook into account its assessment of general economic, market and financial economicconditions and market criteriaits experience in other transactions, as well as its experience in securities valuation and other information as Davidson considered relevant includingknowledge of the banking industry generally. KBW also participated in discussions with management and other representatives and advisorsheld by the managements of HeritageAB and Glacier concerningregarding the past and current business operations, regulatory relations, financial condition and future prospects of their respective companies and such other matters

as KBW deemed relevant to its inquiry. In addition, KBW considered the results of operationsthe efforts undertaken by AB, with KBW’s assistance, to solicit indications of interest from third parties regarding a potential transaction with AB.

In conducting its review and prospects of Heritage and Glacier.

KBW assumed that the merger would be consummated in a manner that complies with the applicable provisions of the Securities Act of 1933, as amended, the Exchange Act, and all other applicable federal and state statutes, rules and regulations. KBW was further advised by representatives of AB that AB relied upon advice from its advisors (other than KBW) or other appropriate sources as to all legal, financial reporting, tax, accounting and regulatory matters with respect to AB, Glacier, the merger and any related transactions, and the merger agreement. KBW did not provide advice with respect to any such matters. KBW assumed, at the direction of AB and without independent verification, that the AB Closing Capital (as defined in the merger agreement) would be no less than the Closing Capital Requirement (as defined in the merger agreement). In addition, at the direction of AB, KBW gave no effect to any potential adjustment to the exchange ratio (as provided in the merger agreement) for purposes of the opinion.

KBW’s opinion addressed only the fairness, from a financial point of view, as of the date of the opinion, letter was deliveredof the exchange ratio in the merger to Heritage’s boardthe holders of directors.

Our opinion does not take into accountAB common shares, without regard to individual circumstances of specific holders or groups of holders with respect to control, voting or other rights or aspects which may distinguish such holders.

We also express KBW expressed no view or opinion as to any other terms or aspects of the merger or any term or aspect of any related transaction (including the bank merger or the actions relating to the ESOP to be undertaken in connection with the merger as provided in the merger agreement), including without limitation, the form or structure of the merger or any such related transaction, any consequences of the merger or any such related transaction to AB, its shareholders, creditors or otherwise, or any terms, aspects, merits or implications of any employment, consulting, voting, support, shareholder or other agreements, arrangements or understandings contemplated or entered into in connection with the merger, any such related transaction, or otherwise. KBW’s opinion was necessarily based upon conditions as they existed and could be evaluated on the date of such opinion and the information made available to KBW through such date. There has been widespread disruption, extraordinary uncertainty and unusual volatility arising from the effects of the COVID-19 pandemic, including the effect of evolving governmental interventions and non-interventions. Developments subsequent to the date of KBW’s opinion may have affected, and may affect, the conclusion reached in KBW’s opinion and KBW did not and does not have an obligation to update, revise or reaffirm its opinion. KBW’s opinion did not address, and KBW expressed no view or opinion with respect to:

In performing its analyses, KBW made numerous assumptions with respect to industry performance, general business, economic, market and financial conditions and other matters, which are beyond the control of KBW, AB and Glacier. Any estimates contained in the analyses performed by KBW are not necessarily indicative of actual values or future results, which may be significantly more or less favorable than suggested by these analyses. Additionally, estimates of the value of businesses or securities do not purport to be appraisals or to reflect the prices at which Glacier’s common stocksuch businesses or Heritage’s common stock will trade following announcementsecurities might actually be sold. Accordingly, these analyses and estimates are inherently subject to substantial uncertainty. In addition, KBW’s opinion was among several factors taken into consideration by the AB Board in making its determination to approve the merger agreement and the merger. Consequently, the analyses described below should not be viewed as determinative of the transaction or at any future time.

For purposes of the financial analyses described below, KBW utilized an implied transaction value for the proposed merger of $49.25 per outstanding AB common share, or approximately $937.8 million in the aggregate (inclusive of the implied value of in-the-money AB stock options), based on the 0.7971x exchange ratio in the proposed merger and the closing price of Glacier common stock on April 1, 2019,May 14, 2021. In addition to the financial analyses described below, KBW reviewed with the AB Board for informational purposes, among other things, implied transaction multiples for the proposed merger (based on the implied transaction value for the merger of $41.00, the consideration represented an implied value$49.25 per outstanding AB common share) of $176.0023.0x AB’s estimated calendar year 2021 earnings per share of Heritage common stock. Based upon(“EPS”) using reported financial information as of orresults for the twelve month periodfiscal quarter ended DecemberMarch 31, 20182021 of AB and other financial and market information described below, Davidson calculated the following transaction ratios:

Stock Price Performance of Glacier

Davidson reviewed the history of the reported trading prices and volume of Glacier common stock and certain stock indices, including the Russell 3000 and the KBW Regional Bank Index. Davidson compared the stock price performance of Glacier with the performance of the Russell 3000 and the KBW Regional Banking Index as follows:

Note: DoesKBW’s analysis showed the following concerning the financial condition of AB and, to the extent publicly available, the selected companies: