SUMMARY

        This summary provides a brief overview of the key aspects of the merger, the Hudson Valley special meeting, the Sterling special meeting, the merger agreement and the offering of shares of Sterling common stock to Hudson Valley stockholders in connection with the merger. This summary identifies those aspects that Sterling and Hudson Valley believe may be most significant to their stockholders. We urge you to read carefully the entire joint proxy statement/prospectus, including the annexes, and the other documents to which we refer in order to fully understand the merger. See "Where You Can Find More Information" beginning on page [    ]. Each item in this summary refers to the page of this joint proxy statement/prospectus on which that subject is discussed in more detail.

In the Merger, Hudson Valley Common Shareholders Will Receive Shares of Sterling Common Stock (page [    ])

        Sterling and Hudson Valley are proposing a strategic merger. If the merger is completed, Hudson Valley common shareholders will receive 1.92 shares of Sterling common stock for each share of Hudson Valley common stock they hold immediately prior to the merger. Sterling will not issue any fractional shares of Sterling common stock in the merger. Hudson Valley shareholders who would otherwise be entitled to a fraction of a share of Sterling common stock upon the completion of the merger will instead receive, for the fraction of a share, an amount in cash based on the Sterling closing share value.For example, if you hold 10 shares of Hudson Valley common stock, you will receive 19 shares of Sterling common stock and a cash payment instead of the 0.2 shares of Sterling common stock that you otherwise would have received (10 shares × 1.92 = 19.2 shares).

        Sterling common stock is listed on the New York Stock Exchange under the symbol "STL," and Hudson Valley common stock is listed on the New York Stock Exchange under the symbol "HVB." The following table shows the closing sale prices of Sterling common stock and Hudson Valley common stock as reported on the New York Stock Exchange on November 4, 2014, the last full trading day before the public announcement of the merger agreement, and on [                        ]March 27, 2015 the last practicable trading day before the date of this joint proxy statement/prospectus. This table also shows the implied value of the merger consideration payable for each share of Hudson Valley common stock, which we calculated by multiplying the closing price of Sterling common stock on those dates by the exchange ratio of 1.92. As previously disclosed, on February 11, 2015, Sterling issued 6,900,000 shares of its $0.01 par value common stock, representing approximately 8% of its outstanding shares prior to giving effect to the issuance, to institutional investors at $13.00 per share. Based on the number of shares of Sterling common stock and Hudson Valley common stock outstanding as of November 4, 2014, the date on which the Hudson Valley board approved the merger agreement and the date on which KBW provided its fairness opinion to the Hudson Valley board, former shareholders of Hudson Valley as a group would have received shares in the merger constituting approximately 31% of the outstanding shares of Sterling common stock immediately after the merger. Following Sterling's February 2015 issuance of 6,900,000 shares of common stock, it is currently expected that former shareholders of Hudson Valley as a group will receive shares in the merger constituting approximately 30% of the outstanding shares of Sterling common stock immediately after the merger. The pro forma ownership percentage of former Hudson Valley shareholders in the combined company was reduced on account of the dilution caused by Sterling's February 2015 issuance. As described in "The Merger Agreement—Covenants and Agreements", other than in the case of stock splits and similar reclassifications, the merger agreement does not restrict the ability of Sterling to issue and sell additional shares of common stock before the completion of the merger, and any such additional issuances would dilute the ownership percentage of former Hudson Valley shareholders upon completion of the merger. Because the exchange ratio in the merger is fixed, the merger agreement does not provide for any increase in the merger consideration to reflect the effect of dilution caused by any additional issuances of common stock by Sterling or any

changes in the price of either Sterling common stock or Hudson Valley common stock prior to completion of the merger.

The Sterling Board Unanimously Recommends that Sterling Stockholders Vote "FOR" the Adoption of the Merger Agreement and the Other Proposals Presented at the Sterling Special Meeting (page [    ])

        The Sterling board has determined that the merger, the merger agreement and the transactions contemplated by the merger agreement are advisable and in the best interests of Sterling and its stockholders and has unanimously approved the merger agreement. The Sterling board unanimously recommends that Sterling stockholders vote "FOR" the adoption of the merger agreement and "FOR" the other proposals presented at the Sterling special meeting. For the factors considered by the Sterling board in reaching its decision to approve the merger agreement, see "The Merger—Sterling's Reasons for the Merger; Recommendation of Sterling's Board of Directors."

        Each of the directors of Sterling and certain of their affiliates have entered into a voting agreement with Hudson Valley, solely in his or her or its capacity as a stockholder of Sterling, pursuant to which they have agreed to vote in favor of the Sterling merger proposal and in favor of any other matter required to be approved by the stockholders of Sterling to facilitate the transactions contemplated by the merger agreement. For more information regarding the voting agreements, see "The Merger Agreement—Voting Agreements."

The Hudson Valley Board Unanimously Recommends that Hudson Valley Shareholders Vote "FOR" the Adoption of the Merger Agreement and the Hudson Valley Adjournment Proposal at the Hudson Valley Special Meeting (page [    ])

        The Hudson Valley board has determined that the merger, the merger agreement and the transactions contemplated by the merger agreement are advisable and in the best interests of Hudson Valley and its shareholders and has unanimously approved the merger agreement. The Hudson Valley board unanimously recommends that Hudson Valley shareholders vote "FOR" the adoption of the merger agreement and "FOR" the Hudson Valley adjournment proposal at the Hudson Valley special meeting. In reaching its decision to approve the merger, the merger agreement and the transactions contemplated by the merger agreement, the Hudson Valley board of directors considered a number of factors, including, without limitation, Hudson Valley's recent financial performance, Sterling's business,

financial condition, results of operations and management, the recent performance of Sterling's common stock on both a historical and prospective basis, the strategic fit between the parties, the potential synergies expected from the merger and the opinion, dated November 4, 2014, of Hudson Valley's financial advisor to the Hudson Valley board as to the fairness, from a financial point of view, of the exchange ratio in the merger. For the other factors considered by the Hudson Valley board in reaching its decision to approve the merger agreement, see "The Merger—Hudson Valley's Reasons for the Merger; Recommendation of the Hudson Valley Board."

The Hudson Valley Board Unanimously Recommends that Hudson Valley Shareholders Vote "FOR" the Hudson Valley Merger-Related Compensation Proposal at the Hudson Valley Special Meeting (page [      ])

        The Hudson Valley board has determined that shareholder approval, on a non-binding and advisory basis, of the compensation of Hudson Valley's named executive officers that is based on or otherwise relates to the merger is advisable and in the best interests of Hudson Valley and its shareholders. The merger-related compensation includes the acceleration of vesting of stock-based awards, the payment and receipt of other benefits under change in control agreements and a consulting agreement, and the acceleration of vesting of retirement benefits under a supplemental deferred compensation agreement and supplemental retirement plans, as more fully described in "The

Merger—Interests of Hudson Valley Directors and Executive Officers in the Merger—Merger-Related Compensation for Hudson Valley's Named Executive Officers" beginning on page [      ].

        The Hudson Valley board unanimously recommends that Hudson Valley shareholders vote "FOR" approval of the Hudson Valley merger-related compensation proposal at the Hudson Valley special meeting.

        In reaching its decision to recommend approval of the Hudson Valley merger-related compensation proposal to Hudson Valley shareholders, the Hudson Valley board of directors, including eight directors (out of a total of ten directors) not receiving any compensation that is subject to the Hudson Valley merger-related compensation proposal, considered, among other things, (1) that the various plans and arrangements pursuant to which change of control, equity acceleration and other payments are required by their terms to be made, have previously formed part of Hudson Valley's overall compensation program for its named executive officers, which program has been disclosed to Hudson Valley shareholders as required by the rules of the SEC in the Compensation Discussion and Analysis and related sections of Hudson Valley's annual proxy statements and which received non-binding shareholder approval at Hudson Valley's annual meetings since 2011, and (2) the necessity of preserving Hudson Valley's business prior to the closing of the merger and in the event the merger is not completed. Each of the directors of Hudson Valley and certain of their affiliates has entered into a voting agreement with Sterling, solely in his or her capacity as a shareholder of Hudson Valley, pursuant to which they have agreed to vote in favor of the Hudson Valley merger proposal and in favor of any other matter required to be approved by the shareholders of Hudson Valley to facilitate the transactions contemplated by the merger agreement. As of the record date, approximately 5,006,468 shares of Hudson Valley common stock, representing approximately 24.9% of the shares of Hudson Valley common stock outstanding on that date, were subject to these voting agreements. For more information regarding the voting agreements, see "The Merger Agreement—Voting Agreements."

Opinion of Hudson Valley's Financial Advisor (page [    ] and Annex D)

        In connection with the merger, Hudson Valley's financial advisor, Keefe, Bruyette & Woods, Inc. (which we refer to as "KBW"), delivered a written opinion, dated November 4, 2014, to the Hudson Valley board of directors as to the fairness, from a financial point of view and as of the date of the opinion, to the holders of Hudson Valley common stock of the exchange ratio in the merger. The full text of the opinion, which describes the procedures followed, assumptions made, matters considered, and qualifications and limitations on the review undertaken by KBW in preparing the opinion, is

attached as Annex D to this joint proxy statement/prospectus. The opinion was for the information of, and was directedprovided to the Hudson Valley board (in its capacity as such) in connection with its consideration of the financial terms of the merger. The opinion did not address the underlying business decision of Hudson Valley to engage in the merger or enter into the merger agreement or constitute a recommendation to the Hudson Valley board in connection with the merger, and it does not constitute a recommendation to any holder of Hudson Valley common stock or any shareholder of any other entity as to how to vote in connection with the merger or any other matter.

        Pursuant to the KBW engagement agreement, Hudson Valley agreed to pay KBW a total cash fee, currently estimated to be approximately $4.3 million, equal to 0.80% of the aggregate merger consideration, $500,000 of which became payable to KBW upon the rendering of its opinion and the balance of which is contingent upon the consummation of the merger. In addition, KBW acted as financial advisor to legacy Sterling Bancorp in 2012 and 2013 in connection with the Provident merger and received a total cash fee of $2,000,000 for such services. In 2015, KBW also acted as a joint book-running manager in connection with Sterling's common stock offering in February 2015 and received total cash fees of approximately $1,500,000 for such services.

For further information, see "The Merger—Opinion of Hudson Valley's Financial Advisor."

        See "The Merger—Certain Unaudited Prospective Financial Information" on page [    ] for unaudited prospective financial information of Hudson Valley and Sterling provided to KBW.

Opinion of Sterling's Financial Advisors (pages [    ] and [    ] and Annexes E and F)

        In connection with the merger, Sterling obtained opinions from each of Jefferies LLC (which we refer to as ``Jefferies") and RBC Capital Markets, LLC (which we refer to as "RBC") as to the fairness, from a financial point of view, of the exchange ratio to Sterling. Sterling determined that, based on the significance of the merger, it would benefit from the advice and fairness opinion of two independent financial advisors, which was consistent with the approach Sterling had taken in the Provident merger, its most recent significant transaction.

        See "The Merger—Certain Unaudited Prospective Financial Information" on page [    ] for unaudited prospective financial information of Hudson Valley and Sterling provided to Jefferies and RBC.

Opinion of Jefferies

        On November 4, 2014, at a meeting of the Sterling board held to evaluate the merger, Jefferies delivered to the Sterling board an oral opinion, confirmed by delivery of a written opinion dated November 4, 2014, to the effect that, as of that date and based on and subject to various assumptions, matters considered and limitations described in Jefferies' opinion, the exchange ratio pursuant to the merger agreement was fair, from a financial point of view, to Sterling. The full text of Jefferies' written opinion is attached as Annex E to this joint proxy statement/prospectus. Sterling stockholders should read the entire opinion for a discussion of, among other things, the assumptions made, procedures followed, matters considered and qualifications and limitations on the review undertaken by Jefferies in rendering its opinion. Jefferies will receive an aggregate fee of $2.5 million for its services, a substantial portion of which is payable contingent upon consummation of the merger. Jefferies has not, in the past two years, provided financial advisory and financing services to Sterling or Hudson Valley other than acting as joint book-running manager in connection with Sterling's common stock offering in February 2015, for which Jefferies received compensation of approximately $1.9 million. For a further discussion of Jefferies's opinion, see "The Merger—Opinion of Jefferies" beginning on page [    ] of this joint proxy statement/prospectus

Opinion of RBC

        Sterling retained RBC to provide an opinion as to the fairness, from a financial point of view, of the consideration to be paid by Sterling in the merger. Sterling selected RBC to act as its financial

advisor based on its qualifications, expertise, reputation and knowledge of Sterling's business and affairs and its experience with community bank holding companies and the industry in which Sterling operates. RBC has delivered a written opinion to the Sterling board to the effect that, as of November 4, 2014 and based upon and subject to the assumptions, limitations, qualifications and other matters set forth therein, the exchange ratio pursuant to the merger agreement was fair, from a financial point of view, to Sterling. RBC's opinion was provided to the Sterling board in connection with the Sterling board's evaluation of the exchange ratio, and did not address any other aspect of the merger or constitute a recommendation to any stockholder as to how such stockholder should vote or act with respect to any matters relating to the merger.

        The full text of RBC's written opinion, dated November 4, 2014, is attached to this joint proxy statement/prospectus as Annex F, and constitutes part of this joint proxy statement/prospectus. The opinion sets forth, among other things, the assumptions made, procedures followed, matters considered and limitations and qualifications of the review undertaken by RBC in rendering its opinion. You should carefully read the opinion in its entirety. In Sterling's engagement letter with RBC, Sterling agreed to pay RBC $250,000 upon delivery of its written opinion, whether or not the opinion is accepted or whether the merger is consummated. RBC has not provided any investment banking or financial advisory services to Sterling or Hudson Valley in the past two years for which it received any fees or other compensation, other than acting as joint book-running manager in connection with Sterling's common stock offering in February 2015, for which RBC and its affiliates received compensation of approximately $850,000. For a further discussion of RBC's opinion, Sterling's prior relationship with RBC and the terms of RBC's engagement, see "The Merger—Opinion of RBC" beginning on page [    ] of this joint proxy statement/prospectus.

What Holders of Hudson Valley Equity-Based Awards Will Receive (page [    ])

        Restricted Stock Units:    At the effective time of the merger, each restricted stock unit award granted by Hudson Valley will vest, with any performance-based vesting condition deemed satisfied to the extent provided in the applicable award agreement (or, if not provided in the applicable award agreement, then deemed satisfied at target), and be converted into the right to receive a cash amount equal to (i) the number of shares subject to such restricted stock unit award multiplied by (ii) the Hudson Valley equity award consideration, less applicable tax withholdings.

        Stock Options:    Each in-the-money stock option granted by Hudson Valley will vest in full and be converted into the right to receive a cash amount equal to the product of (i) the number of shares subject to such stock option multiplied by (ii) the excess of the Hudson Valley equity award consideration over the exercise price of such option, less applicable tax withholdings. Any out-of-the-money stock options granted by Hudson Valley will be cancelled for no consideration.

        Restricted Shares:    Each restricted share of Hudson Valley Common Stock will vest, with any performance-based vesting condition deemed satisfied to the extent provided in the applicable award agreement, and be converted into the right to receive 1.92 shares of Sterling Common Stock, less applicable tax withholdings.

        Based on a per share price of Hudson Valley common stock equal to the average closing price per share over the first five business days following the announcement of the merger agreement, the estimated aggregate amount that would be payable in settlement of outstanding restricted stock units and outstanding stock options if the merger occurred on March 6,27, 2015 is $882,700 and $143,300, respectively. If the merger occurred on March 6,27, 2015, Sterling would issue an estimated aggregate 338,453402,103 shares of Sterling common stock in exchange for the outstanding restricted shares of Hudson Valley common stock. The major recipients of such amounts are Hudson Valley's executive officers, Stephen R. Brown, James J. Landy, Michael P. Maloney, James P. Blose, Michael E. Finn, Michael J. Indiveri, John M. Swadba, Andrew J. Reinhart and Scott J. Skorobohaty, who will receive an aggregate of $3.27$4.18 million in settlement of their equity awards. For additional information on these recipients, see "The Merger—Interests of Hudson Valley's Directors and Executive Officers in the Merger."

Sterling Will Hold its Special Meeting on [            ] (page [    ])

        The special meeting of Sterling stockholders will be held on [            ], at [            ] local time, at [            ]. At the Sterling special meeting, Sterling stockholders will be asked to approve the Sterling merger proposal and approve the Sterling adjournment proposal.

        Only holders of record of Sterling common stock at the close of business on February 27, 2015 will be entitled to vote at the Sterling special meeting. Each share of Sterling common stock is entitled to one vote on each proposal to be considered at the Sterling special meeting. As of the record date, there were 91,075,321 shares of Sterling common stock entitled to vote at the special meeting. As of the record date, the directors and executive officers of Sterling and their affiliates (certain of whom have entered into a voting agreement with Hudson Valley, solely in his or her or its capacity as a stockholder of Sterling, pursuant to which they have agreed to vote in favor of the Sterling merger proposal and in favor of any other matter required to be approved by the stockholders of Sterling to facilitate the transactions contemplated by the merger agreement) beneficially owned and were entitled to vote approximately 3,098,780 shares of Sterling common stock representing approximately 3.4% of the shares of Sterling common stock outstanding on that date. The Sterling stockholders that are party to these voting agreements beneficially own and are entitled to vote, in the aggregate, approximately 5,480,452 shares of Sterling common stock, allowing them to exercise approximately 6.0% of the voting power of Sterling common stock outstanding as of the record date. Based on the number of shares of Sterling common stock subject to the Sterling voting agreements, stockholders holding an additional 44.0% of the outstanding shares of Sterling common stock would have to vote their shares in favor of the Sterling merger proposal in order for such proposal to be approved.

        To approve the Sterling merger proposal, at least a majority of the shares of Sterling common stock outstanding and entitled to vote thereon must be voted in favor of such proposal. If you mark "ABSTAIN" on your proxy, fail to submit a proxy or vote in person at the Sterling special meeting or fail to instruct your bank or broker how to vote with respect to the Sterling merger proposal, it will have the same effect as a vote "AGAINST" the proposal.

        The Sterling adjournment proposal will be approved if a majority of the votes cast at the Sterling special meeting are voted in favor of such proposal. If you mark "ABSTAIN" on your proxy, fail to submit a proxy or vote in person at the Sterling special meeting or fail to instruct your bank or broker how to vote with respect to the Sterling adjournment proposal, it will have no effect on the proposal.

Hudson Valley Will Hold its Special Meeting on [            ] (page [    ])

        The special meeting of Hudson Valley shareholders will be held on [            ], at [            ] local time, at [            ]. At the Hudson Valley special meeting, Hudson Valley shareholders will be asked to approve the Hudson Valley merger proposal, approve the Hudson Valley merger-related compensation proposal and approve the Hudson Valley adjournment proposal.

        Only holders of record of Hudson Valley common stock at the close of business on March 3, 2015 will be entitled to vote at the Hudson Valley special meeting. Each share of Hudson Valley common stock is entitled to one vote on each proposal to be considered at the Hudson Valley special meeting. As of the record date, there were 20,072,296 shares of Hudson Valley common stock entitled to vote at the special meeting. As of the record date, the directors and executive officers of Hudson Valley and their affiliates (certain of whom have entered into a voting agreement with Sterling solely in his or her or its capacity as a shareholder of Hudson Valley, pursuant to which they have agreed to vote in favor of the Hudson Valley merger proposal) beneficially owned and were entitled to vote approximately 5,094,219 shares of Hudson Valley common stock representing approximately 25.4% of the shares of Hudson Valley common stock outstanding on that date. As of the record date, the Hudson Valley shareholders subject to the voting agreements beneficially owned and were entitled to vote, in the aggregate, approximately 5,006,468 shares of the Hudson Valley common stock, allowing them to

exercise approximately 24.9% of the voting power of Hudson Valley common stock outstanding as of the record date. Based on the number of shares of Hudson Valley common stock subject to the Hudson Valley voting agreements, shareholders holding an additional 41.8% of the outstanding shares of Hudson Valley common stock would have to vote their shares in favor of the Hudson Valley merger proposal in order for such proposal to be approved.

        To approve the Hudson Valley merger proposal, at least two-thirds of the shares of Hudson Valley common stock outstanding and entitled to vote thereon must be voted in favor of such proposal. If you mark "ABSTAIN" on your proxy, fail to submit a proxy or vote in person at the Hudson Valley special meeting or fail to instruct your bank or broker how to vote with respect to the Hudson Valley merger proposal, it will have the same effect as a vote "AGAINST" the proposal.

        The Hudson Valley merger-related compensation proposal and the Hudson Valley adjournment proposal will each be approved if a majority of the votes cast on each proposal at the Hudson Valley special meeting are voted in favor of each proposal at the Hudson Valley special meeting. If you mark "ABSTAIN" on your proxy, fail to submit a proxy or vote in person at the Hudson Valley special meeting or fail to instruct your bank or broker how to vote with respect to either proposal, it will have no effect on the Hudson Valley merger-related compensation proposal or the Hudson Valley adjournment proposal. As described above, each of the directors of Hudson Valley and certain of their affiliates, including Stephen R. Brown and James J. Landy, whose merger-related compensation is the subject of the Hudson Valley merger-related compensation proposal as a named executive officer of Hudson Valley, and who beneficially own and are entitled to vote approximately 1.9% of the outstanding shares of Hudson Valley common stock as of the record date, has entered into a voting agreement with Sterling, solely in his or her capacity as a shareholder of Hudson Valley, pursuant to which they have agreed to vote in favor of the Hudson Valley merger proposal and in favor of any other matter required to be approved by the shareholders of Hudson Valley to facilitate the transactions contemplated by the merger agreement. Each of the approximately 5,006,468 shares of Hudson Valley common stock subject to the Hudson Valley voting agreements is expected to be voted in favor of the Hudson Valley merger-related compensation proposal.

The Merger Is Intended to Be Tax-Free to Holders of Hudson Valley Common Stock as to the Shares of Sterling Common Stock They Receive (page [    ])

        The merger is intended to qualify as a "reorganization" within the meaning of Section 368(a) of the Code, and it is a condition to the respective obligations of each of Sterling and Hudson Valley to complete the merger that it receives a legal opinion to that effect. Accordingly, the merger generally is expected to be tax-free to a holder of Hudson Valley common stock for U.S. federal income tax purposes as to the shares of Sterling common stock he or she receives in the merger, except for any gain or loss that may result from the receipt of cash instead of fractional shares of Sterling common stock that such holder of Hudson Valley common stock would otherwise be entitled to receive.

        In connection with this registration statement, each of Wachtell, Lipton, Rosen & Katz and Day Pitney LLP has delivered its opinion to the effect that, on the basis of the facts and representations set forth in such opinions and in certificates obtained from officers of Sterling and Hudson Valley, and subject to the qualifications, exceptions, assumptions, beliefs and limitations described herein and in such opinions, (i) the merger will qualify as a "reorganization" within the meaning of Section 368(a) of the Code and (ii) the discussion set forth herein under the sub-heading "Tax Consequences of the Merger Generally" constitutes their opinion as to the material U.S. federal income tax consequences of the merger to holders of Hudson Valley common stock. The opinions of Wachtell, Lipton, Rosen & Katz and Day Pitney LLP are filed as exhibits 8.1 and 8.2, respectively, to the registration statement of which this joint proxy statement/prospectus forms a part.

        For further information, see "Material U.S. Federal Income Tax Consequences of the Merger."

        The U.S. federal income tax consequences described above may not apply to all holders of Hudson Valley common stock. Your tax consequences will depend on your individual situation. Accordingly, we strongly urge you to consult your independent tax advisor for a full understanding of the particular tax consequences of the merger to you.

Hudson Valley's Officers and Directors Have Financial Interests in the Merger that Differ from Your Interests (page [    ])

        Hudson Valley shareholders should be aware that some of Hudson Valley's directors and executive officers have interests in the merger and have arrangements that are different from, or in addition to, those of Hudson Valley shareholders generally. Hudson Valley's board of directors was aware of these interests and considered these interests, among other matters, when making its decision to approve the merger agreement, and in recommending that Hudson Valley shareholders vote in favor of adopting the merger agreement.

        The material interests considered by Hudson Valley's board of directors were as follows:

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The terms of the restricted stock, restricted stock unit and stock option awards held by Hudson Valley directors and executive officers provide for accelerated vesting of the awards upon a change in control such as the merger. The aggregate value of these equity awards, which were granted on various dates in the past, is approximately $3.47$4.61 million.



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Subject to the terms of the merger agreement, Hudson Valley has, in consultation with Sterling, accelerated the payment of certain compensatory amounts so that they were paid in 2014 for tax planning purposes with respect to Sections 280G and 4999 of the Code. Such amounts included the acceleration of the vesting date of the Hudson Valley restricted stock, restricted stock units and 2014 bonuses under the Annual Incentive Plan and the Long Term Incentive Plan.



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Hudson Valley previously entered into change of control agreements on April 10, 2014 and July 7, 2014 with a number of its executive officers, which entitle each of them to certain payments and benefits upon a qualifying termination in connection with a change in control such as the merger. The aggregate benefit from these change in control agreements is approximately $6.65$6.71 million, assuming each executive officer has a qualifying termination event in connection with the merger.



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Hudson Valley previously entered into a consulting agreement, dated October 6, 2014, with its retiring executive chairman, which entitles him to terminate the consulting agreement and receive certain payments and benefits in connection with a change in control such as the merger. The aggregate benefit from this consulting agreement is approximately $1.02 million.



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In connection with the execution of the merger agreement, Hudson Valley's president and chief executive officer entered into a one-year consulting agreement, dated as of November 4, 2014, with Sterling National Bank, which entitles him to the receipt of consulting fees for providing services in connection with the integration of Sterling and Hudson Valley. The aggregate benefit from this consulting agreement is $850,000.



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Hudson Valley's supplemental deferred compensation agreement with an executive officer, dated as of October 1, 2010, and Hudson Valley's supplemental retirement plans each provide for accelerated vesting of retirement benefits in connection with a change in control such as the merger. The aggregate benefit from the supplemental deferred compensation agreement and the supplemental retirement plans is approximately $5.46 million.



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Four current Hudson Valley directors will join the board of Sterling and Sterling National Bank upon completion of the merger, and Sterling will also establish an advisory board consisting of Hudson Valley directors who are not joining the boards of Sterling and Sterling National Bank

and who wish to serve on the advisory board. Members of the Sterling board are expected to receive compensation consistent with the compensation paid to current non-employee directors of Sterling, as described in the definitive proxy statement for Sterling's 2014 annual meeting of stockholders, which was filed with the SEC on January 10, 2014, and is incorporated by reference into this joint proxy statement/prospectus. During 2014, such compensation included an annual retainer fee of $24,000 and per-meeting fees. Directors are also eligible to receive stock awards and stock option grants and are eligible to participate in the Deferred Director Fee Plan. Members of the Sterling advisory board will be eligible to receive fees for their service on the advisory board that are substantially similar to the fees received by members of Hudson Valley's Business Development Board as of the date of the merger agreement, which in 2014 totaled approximately $1,250 in value per person. As of the date of this joint proxy statement/prospectus, Sterling had not yet identified which of the current Hudson Valley directors will join the boards of Sterling and Sterling National Bank upon completion of the merger.

        Subject to the assumptions and limitations discussed in this joint proxy statement/prospectus under the sections "The Merger—Interests of Hudson Valley's Directors and Executive Officers in the Merger" and "The Merger—Merger-Related Compensation for Hudson Valley's Named Executive Officers," and assuming the effective time of the merger occurred on March 6,27, 2015 and a per share price of Hudson Valley common stock equal to the average closing price per share over the first five business days following the announcement of the merger agreement, the aggregate value that will be received by directors and executive officers as a consequence of the merger is approximately $19.45$18.70 million. Of this amount, each named executive officer currently employed with or providing services to Hudson Valley will receive the following: Stephen R. Brown will receive approximately $7.36$7.17 million, Michael J. Indiveri will receive approximately $1.33$1.25 million, James J. Landy will receive approximately $1.42$1.33 million, James P. Blose will receive approximately $1.43$1.34 million and Scott J. Skorobohaty will receive approximately $0.97$0.98 million. For a more complete description of these interests, see "The Merger—Interests of Hudson Valley's Directors and Executive Officers in the Merger."

Hudson Valley Shareholders Will NOT Be Entitled To Assert Dissenters' Rights (page [    ])

        Under the New York Business Corporation Law (which we refer to as the "NYBCL"), which is the law under which Hudson Valley is incorporated, the holders of Hudson Valley common stock will not be entitled to any appraisal rights or dissenters' rights in connection with the merger if, on the record date for the Hudson Valley special meeting, their shares are listed on a national securities exchange. Hudson Valley common stock is currently listed on the New York Stock Exchange, a national securities exchange, and is expected to continue to be so listed on the record date for the Hudson Valley special meeting. Accordingly, Hudson Valley shareholders will not be entitled to assert dissenters' rights in connection with the merger. For more information, see "The Merger—Dissenters' Rights in the Merger."

Conditions that Must Be Satisfied or Waived for the Merger To Occur (page [    ])

        Currently, Hudson Valley and Sterling expect to complete the merger in the second calendar quarter of 2015. As more fully described in this joint proxy statement/prospectus and in the merger agreement, the completion of the merger depends on a number of conditions being satisfied or, where legally permissible, waived. These conditions include (1) adoption of the merger agreement by Hudson Valley's shareholders and by Sterling's stockholders, (2) authorization for listing on the New York Stock Exchange of the shares of Sterling common stock to be issued in the merger, (3) the receipt of required regulatory approvals, including the approval of the Board of Governors of the Federal Reserve System (which we refer to as the "Federal Reserve Board") and the Office of the Comptroller of the Currency (which we refer to as the "OCC"), (4) effectiveness of the registration statement of which

this joint proxy statement/prospectus is a part, (5) the absence of any order, injunction or other legal restraint preventing the completion of the merger or making the completion of the merger illegal, (6) subject to the materiality standards provided in the merger agreement, the accuracy of the representations and warranties of Sterling and Hudson Valley in the merger agreement, (7) performance in all material respects by each of Sterling and Hudson Valley of its obligations under the merger agreement and (8) receipt by each of Sterling and Hudson Valley of an opinion from its counsel as to certain tax matters.

        Neither Hudson Valley nor Sterling can be certain when, or if, the conditions to the merger will be satisfied or waived, or that the merger will be completed.

Termination of the Merger Agreement (page [    ])

        The merger agreement can be terminated at any time prior to completion of the merger in the following circumstances:

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by mutual written consent of Sterling and Hudson Valley, if the board of directors of each so determines by a vote of a majority of the members of its entire board;



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by the Sterling board or the Hudson Valley board if any governmental entity that must grant a requisite regulatory approval has denied approval of the transactions contemplated by the merger agreement and such denial has become final and nonappealable or any governmental entity of competent jurisdiction has issued a final nonappealable order permanently enjoining or otherwise prohibiting or making illegal the consummation of the transactions contemplated by the merger agreement, unless the failure to obtain a requisite regulatory approval is due to the failure of the party seeking to terminate the merger agreement to perform or observe its covenants and agreements under the merger agreement;



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by the Sterling board or the Hudson Valley board if the merger has not been completed on or before the one year anniversary of the date of the merger agreement (which we refer to as the "termination date"), unless the failure of the merger to be completed by such date is due to the failure of the party seeking to terminate the merger agreement to perform or observe its covenants and agreements under the merger agreement;



•

by the Sterling board or the Hudson Valley board (provided that the terminating party is not then in material breach of any representation, warranty, covenant or other agreement contained in the merger agreement) if there is a breach of any of the covenants or agreements or any of the representations or warranties (or any such representation or warranty ceases to be true) set forth in the merger agreement on the part of the other party which either individually or in the aggregate would constitute, if occurring or continuing on the date the merger is completed, the failure of a closing condition of the terminating party and which is not cured within 45 days following written notice to the party committing such breach, or by its nature or timing cannot be cured during such period (or such fewer days as remain prior to the termination date);



•

by Hudson Valley, if the Sterling board (1) fails to recommend in this joint proxy statement/prospectus that the stockholders of Sterling adopt the merger agreement, or withdraws, modifies or qualifies such recommendation in a manner adverse to Hudson Valley, or resolves to do so, or fails to reaffirm such recommendation within two business days after Hudson Valley requests in writing that such action be taken, or (2) breaches certain obligations, including with respect to calling a meeting of its stockholders and recommending that they adopt the merger agreement, in any material respect; or



•

by Sterling, if the Hudson Valley board (1) fails to recommend in this joint proxy statement/prospectus that the shareholders of Hudson Valley adopt the merger agreement, or withdraws, modifies or qualifies such recommendation in a manner adverse to Sterling, or resolves to do so,

or fails to reaffirm such recommendation within two business days after Sterling requests in writing that such action be taken, or fails to recommend against acceptance of a tender offer or exchange offer for outstanding Hudson Valley common stock that has been publicly disclosed (other than by Sterling or an affiliate of Sterling) within ten business days after the commencement of such tender or exchange offer, (2) recommends or endorses an acquisition proposal, or (3) breaches certain obligations, including with respect to the non-solicitation of acquisition proposals or calling a meeting of its shareholders and recommending that they adopt the merger agreement, in any material respect.

Termination Fee (page [    ])

        If the merger agreement is terminated under certain circumstances, including circumstances involving alternative acquisition proposals and changes in the recommendation of the Hudson Valley board, or changes in the recommendation of the Sterling board, Hudson Valley or Sterling may be required to pay to the other party a termination fee equal to $20 million. These termination fees could discourage other companies from seeking to acquire or merge with Hudson Valley.

Regulatory Approvals Required for the Merger (page [    ])

        Subject to the terms of the merger agreement, both Hudson Valley and Sterling have agreed to cooperate with each other and use their reasonable best efforts to obtain all regulatory approvals necessary or advisable to complete the transactions contemplated by the merger agreement. These approvals include approvals from, among others, the Federal Reserve Board and the OCC. Sterling and Hudson Valley have filed applications and notifications to obtain regulatory approvals from the Federal Reserve Board and the OCC.

        Although neither Hudson Valley nor Sterling knows of any reason why it cannot obtain these regulatory approvals in a timely manner, Hudson Valley and Sterling cannot be certain when or if they will be obtained.

The Rights of Hudson Valley Shareholders Will Change as a Result of the Merger (page [    ])

        The rights of Hudson Valley shareholders will change as a result of the merger due to differences in Sterling's and Hudson Valley's governing documents and states of incorporation. The rights of Hudson Valley shareholders are governed by New York law and by Hudson Valley's certificate of incorporation and bylaws, each as amended to date. Upon the completion of the merger, Hudson Valley shareholders will become stockholders of Sterling, as the continuing legal entity in the merger, and the rights of Hudson Valley shareholders will therefore be governed by Delaware law and Sterling's certificate of incorporation and bylaws.

        These material differences include the following:

•

Sterling's certificate of incorporation provides that Sterling stockholders owning in excess of 10% of the then-outstanding shares of Sterling common stock are not entitled or permitted to any vote in respect of the shares held in excess of the 10% limit, whereas Hudson Valley's organizational documents do not impose voting restrictions on shares held in excess of a 10% limit.



•

Directors on the Hudson Valley board are elected annually, whereas directors on the Sterling board are currently divided into three classes, with each class of directors serving for successive three-year terms so that each year the term of only one class of directors expires.



•

Hudson Valley shareholders may remove directors from the Hudson Valley board with or without cause by the vote of a majority of all outstanding shares of Hudson Valley entitled to vote, whereas Sterling stockholders may remove directors from the Sterling board only for cause

and only by the affirmative vote of holders of 80% of shares entitled to vote in the election of directors.

•

Hudson Valley shareholders may fill director vacancies on the Hudson Valley board at a meeting of Hudson Valley shareholders called for that purpose, whereas only the Sterling board may fill director vacancies on the Sterling board.



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Special meetings of Hudson Valley shareholders may be called by one or more shareholders owning, in the aggregate, not less than 50% of the stock of Hudson Valley, whereas special meetings of Sterling stockholders may only be called by the Sterling board.



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Sterling's certificate of incorporation and Delaware law contain provisions concerning business combinations with interested stockholders which differ from the relevant provisions of New York law with respect to, among other things, the definition of what constitutes an "interested shareholder" or "interested stockholder" and requirements for stockholder approval of such business combinations.



•

Hudson Valley shareholders may amend Hudson Valley's bylaws by the vote of a majority of outstanding shares of Hudson Valley common stock, whereas Sterling stockholders may amend Sterling's bylaws by the vote of the holders of 80% of the voting power of Sterling.

        See "Comparison of Stockholders' Rights" for a more detailed description of these and other differences in stockholders' rights under each of the Sterling and Hudson Valley governing law and documents.

Information About the Companies (page [        ])

Sterling Bancorp

        Sterling Bancorp is a Delaware corporation that owns all of the outstanding shares of common stock of Sterling National Bank. At December 31, 2014, Sterling had, on a consolidated basis, assets of $7.4 billion, deposits of $5.2 billion and stockholders' equity of $975.2 million. Sterling National Bank, a growing full-service bank founded in 1888, is headquartered in Montebello, New York and is the principal bank subsidiary of Sterling. With $7.4 billion in assets and 829 full-time equivalent employees, Sterling National Bank accounts for substantially all of Sterling's consolidated assets and net income. Sterling National Bank is a growing financial services firm that specializes in the delivery of service and solutions to business owners, their families, and consumers in communities within the greater New York metropolitan region through 21 teams of dedicated relationship managers and 32 full-service financial centers.

        Sterling's stock is traded on the New York Stock Exchange under the symbol "STL."

        Sterling's principal office is located at 400 Rella Blvd., Montebello, New York 10901, and its telephone number at that location is (845) 369-8040. Additional information about Sterling and its subsidiaries is included in documents incorporated by reference in this joint proxy statement/prospectus. See "Where You Can Find More Information," beginning on page [        ].

Hudson Valley Holding Corp.

        Hudson Valley is a New York corporation that owns all of the outstanding shares of common stock of Hudson Valley Bank, N.A., a national banking association established in 1972, with operational headquarters in Westchester County, New York. At December 31, 2014, Hudson Valley had, on a consolidated basis, assets of $3.1 billion, deposits of $2.8 billion and stockholders' equity of $297.6 million. Hudson Valley Bank derives substantially all of its revenue and income from providing banking and related services to businesses, professionals, municipalities, not-for-profit organizations and individuals within its market area. Its principal customers are businesses, professionals, municipalities,

not-for-profit organizations and individuals. Hudson Valley Bank has seventeen branch offices in Westchester County, New York, four in Manhattan, New York, four in Bronx County, New York, two in Rockland County, New York, and one in Kings County, New York.

        Hudson Valley's stock is traded on the New York Stock Exchange under the symbol "HVB."

        Hudson Valley's principal executive offices are located at 21 Scarsdale Road, Yonkers, New York 10707 and its telephone number at that location is (914) 961-6100. Additional information about Hudson Valley and its subsidiaries is included in documents incorporated by reference in this joint proxy statement/prospectus. See "Where You Can Find More Information," beginning on page [        ].

Litigation Relating to the Merger (page [        ])

        In connection with the merger, a purported Hudson Valley shareholder has filed a putative class action lawsuit against Hudson Valley, its directors, and Sterling. The amended complaint alleges that Hudson Valley's directors breached their fiduciary duties by failing to run an adequate sales process, agreeing to preclusive provisions in the merger agreement, and failing to disclose all material information in connection with the merger. The amended complaint further alleges that Sterling aided and abetted these alleged breaches. Among other remedies, the plaintiff seeks to enjoin the completion of the merger. The outcome of any such litigation is uncertain. If the case is not resolved, this lawsuit could prevent or delay completion of the merger and result in costs to Sterling and Hudson Valley, including any costs associated with the indemnification of directors and officers. Shareholder plaintiffs may file additional lawsuits against Hudson Valley, Sterling, and/or the directors and officers of either company in connection with the merger. The defense or settlement of any lawsuit or claim that remains unresolved at the time the merger is completed may adversely affect the combined company's business, financial condition, results of operations, and cash flows.

Risk Factors (page [        ])

        You should consider all the information contained in or incorporated by reference into this joint proxy statement/prospectus in deciding how to vote for the proposals presented in the joint proxy statement/prospectus. In particular, you should consider the factors described in detail under "Risk Factors," including the following:

•

Because the market price of Sterling common stock will fluctuate, Hudson Valley shareholders cannot be certain of the market value of the merger consideration they will receive.



•

The market price of Sterling common stock after the merger may be affected by factors different from those affecting the shares of Hudson Valley or Sterling currently.



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Regulatory approvals may not be received, may take longer than expected or may impose conditions that are not presently anticipated or that could have an adverse effect on the combined company following the merger.



•

Combining the two companies may be more difficult, costly or time consuming than expected and the anticipated benefits and cost savings of the merger may not be realized.



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A significant portion of Sterling's and Hudson Valley's loan portfolios consist of commercial real estate loans in the greater New York region, and the merger may continue or increase the industry and geographic concentration of the combined company and result in increased risk and earnings volatility.



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The unaudited pro forma condensed combined financial statements included in this document are preliminary and the actual financial condition and results of operations after the merger may differ materially.

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Certain of Hudson Valley's directors and executive officers have interests in the merger that may differ from the interests of Hudson Valley's shareholders.



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Termination of the merger agreement could negatively impact Hudson Valley or Sterling.



•

Hudson Valley and Sterling will be subject to business uncertainties and contractual restrictions while the merger is pending.



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If the merger is not completed, Sterling and Hudson Valley will have incurred substantial expenses without realizing the expected benefits of the merger.



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The merger agreement limits Hudson Valley's ability to pursue acquisition proposals and requires either company to pay a termination fee of $20 million under limited circumstances, including circumstances relating to acquisition proposals for Hudson Valley. Additionally, certain provisions of Hudson Valley's articles of incorporation and bylaws may deter potential acquirers.



•

The shares of Sterling common stock to be received by Hudson Valley shareholders as a result of the merger will have different rights from the shares of Hudson Valley common stock.



•

Holders of Hudson Valley and Sterling common stock will have a reduced ownership and voting interest after the merger and will exercise less influence over management.



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Hudson Valley shareholders will not have dissenters' or appraisal rights in the merger.



•

Pending litigation against Hudson Valley and Sterling could result in an injunction preventing the completion of the merger or a judgment resulting in the payment of damages.

SELECTED CONSOLIDATED HISTORICAL FINANCIAL DATA OF STERLING

        The following selected consolidated financial information for the fiscal years ended September 30, 2010 through September 30, 2014 is derived from audited financial statements of Sterling. On January 27, 2015, the Sterling Board approved a change in Sterling's fiscal year end from September 30 to December 3l and approved an amendment to Sterling's bylaws to state and effect the change, effective December 31, 2014. The following selected consolidated information for the three months ended December 31, 2014 and 2013 is derived from audited and unaudited financial statements, respectively, of Sterling included in the Transition Report on Form 10-K filed by Sterling for the transition period from October 1, 2014 to December 31, 2014. The following consolidated financial information, and the financial information of Sterling contained in the remainder of this joint proxy statement/prospectus, gives effect to the merger of legacy Sterling Bancorp with and into Provident New York Bancorp (which we refer to as "Provident"), with Provident, the predecessor company to Sterling, as the surviving entity (which merger we refer to as the "Provident merger"), as of October 31, 2013, the date that the Provident merger was completed. Selected unaudited pro forma financial information for the fiscal years ended September 30, 2013 and September 30, 2014, reflecting the Provident Merger assuming it was completed as of October 1, 2012, is set forth in Sterling's Transition Report on Form 10-K for the transition period from October 1, 2014 to December 31, 2014, which is incorporated by reference into this joint proxy statement/prospectus. You should not assume the results of operations for any past periods indicate results for any future period. You should read this information in conjunction with Sterling's consolidated financial statements and related notes thereto included in Sterling's Annual Report on Form 10-K for the fiscal year ended September 30, 2014 and in Sterling's Transition Report on Form 10-K for the transition period from October 1, 2014 to December 31, 2014, which are incorporated by reference into this joint proxy statement/prospectus. See "Where You Can Find More Information."

SELECTED CONSOLIDATED HISTORICAL FINANCIAL DATA OF HUDSON VALLEY

        The following selected consolidated financial information for the calendar years ended December 31, 2010 through December 31, 2014 is derived from audited financial statements of Hudson Valley. You should not assume the results of operations for any past periods indicate results for any future period. You should read this information in conjunction with Hudson Valley's consolidated financial statements and related notes thereto included in Hudson Valley's Annual Report on Form 10-K for the year ended December 31, 2014, which is incorporated by reference into this joint proxy statement/prospectus. See "Where You Can Find More Information."

ADJUSTED UNAUDITED HUDSON VALLEY INFORMATION
(TO ACCOUNT FOR STERLING'S TRANSITION PERIOD)

        On January 27, 2015, the Sterling Board approved a change in Sterling's fiscal year end from September 30 to December 31 and approved an amendment to Sterling's bylaws to state and effect the change, effective December 31, 2014. Sterling filed a Transition Report on Form 10-K for the transition period from October 1, 2014 to December 31, 2014. In order to provide holders with comparable information, for purposes of the unaudited pro forma information, we have computed certain financial information for Hudson Valley as if Hudson Valley had a comparable transition period from October 1, 2014 to December 31, 2014. The information is unaudited and is derived from Hudson Valley's audited financial statements as of December 31, 2014 and its unaudited financial statements as of September 30, 2014. Management of Sterling and Hudson Valley believe this presentation provides holders with better information given the presentation of comparable results for equal three month periods.

        The table below contains the pro forma income statement of Hudson Valley for the three months ended December 31, 2014. The information was derived as follows:

        For each line item, the information for the nine months ended September 30, 2014 (from Hudson's Valley's Quarterly Report on Form 10-Q for the nine months ended September 30, 2014) was subtracted from the information for the twelve months ended December 31, 2014 (from Hudson Valley's Annual Report on Form 10-K for the year ended December 31, 2014). This produces the information for the three months ended December 31, 2014.

ADJUSTED UNAUDITED HUDSON VALLEY INFORMATION
(TO ACCOUNT FOR DIFFERING FISCAL YEAR ENDS)

        Sterling's most recent fiscal year was the fiscal year ended September 30, 2014, and Hudson Valley's most recent fiscal year end was December 31, 2014. In order to provide holders with comparable information, for purposes of the unaudited pro forma information, we have computed certain financial information for Hudson Valley as if Hudson Valley's most recent fiscal year end was September 30, 2014. This information is unaudited and derived from Hudson Valley's audited financial statements as of December 31, 2013 and its unaudited financial statements as of September 30, 2014 and September 30, 2013. Management of Sterling and Hudson Valley believe this presentation provides holders with better information given the presentation of comparable results for equal twelve month periods.

        The table below contains the pro forma income statement of Hudson Valley for the twelve months ended September 30, 2014. This information was derived as follows:

1.

For each line item, the information for the nine months ended September 30, 2013 (from Hudson Valley's Quarterly Report on Form 10-Q for the nine months ended September 30, 2013) was subtracted from the information for the twelve months ended December 31, 2013 (from Hudson Valley's Annual Report on Form 10-K for the year ended December 31, 2013). This produces the information for the three months ended December 31, 2013.



2.

The information for the three months ended December 31, 2013 was then added to the information for the nine months ended September 30, 2014 (from Hudson Valley's Quarterly Report on Form 10-Q for the nine months ended September 30, 2014) to derive information for the twelve months ended September 30, 2014.