Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes [X] No [ ].

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). Yes [X] No [ ].

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act. (Check one):

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. [ ] 

The accounting and reporting policies of the Company and its subsidiaries conform to U.S. generally accepted accounting principles ("GAAP") and general practices within the banking industry. The accompanying consolidated financial statements do not include certain information and note disclosures required by GAAP for complete annual financial statements. Therefore, these financial statements should be read in conjunction with the Company's 20162017 Annual Report on Form 10-K ("20162017 10-K"). The Company uses the accrual basis of accounting for financial reporting purposes. Certain reclassifications were made to prior year amounts to conform to the current year presentation.

The accounting policies related to business combinations, loans, the allowance for credit losses, and derivative financial instruments are presented below. For a summary of all other significant accounting policies, see Note 1, "Summary of Significant Accounting Policies," in the Company's 20162017 10-K.

Acquired and covered loans are separated into (i) non-purchased credit impaired ("non-PCI") and (ii) purchased credit impaired ("PCI") loans. Non-PCI loans include loans that did not have evidence of credit deterioration since origination at the acquisition date. PCI loans include loans that had evidence of credit deterioration since origination and for which it was probable at acquisition that the Company would not collect all contractually required principal and interest payments. Evidence of credit deterioration

was evaluated using various indicators, such as past due and non-accrual status. Leases and revolving loans do not qualify to be accounted for as PCI loans and are accounted for as non-PCI loans.

The acquisition adjustment related to non-PCI loans is amortized into interest income over the contractual life of the related loans. If an acquired non-PCI loan is renewed subsequent to the acquisition date, any remaining acquisition adjustment is accreted into interest income and the loan is considered a new loan that is no longer classified as an acquired loan.

PCI loans are accounted for based on estimates of expected future cash flows. To estimate the fair value, the Company generally aggregates purchased consumer loans and commercial loans into pools of loans with common risk characteristics, such as delinquency status, credit score, and internal risk ratings. The fair values of larger balance commercial loans are estimated on an individual basis. Expected future cash flows in excess of the fair value of loans at the purchase date ("accretable yield") are recorded as interest income over the life of the loans if the timing and amount of the expected future cash flows can be reasonably estimated. The non-accretable yield represents the difference between contractually required payments and the expected future cash flows determined at acquisition. Subsequent increases in expected future cash flows are offset against the allowance for credit losses to the extent an allowance has been established or otherwise recognized as interest income prospectively. The present value of any decreases in expected future cash flows is recognized by recording a charge-off through the allowance for loan losses or providing an allowance for loan losses.

Non-accrual Loans – Generally, corporate loans are placed on non-accrual status (i) when either principal or interest payments become 90 days or more past due unless the credit is sufficiently collateralized and in the process of renewal or collection, or (ii) when an individual analysis of a borrower's creditworthiness warrants a downgrade to non-accrual regardless of past due status. When a loan is placed on non-accrual status, unpaid interest credited to income in the current year is reversed, and unpaid interest accrued in prior years is charged against the allowance for loan losses. After the loan is placed on non-accrual status, all debt service payments are applied to the principal on the loan. Future interest income may only be recorded on a cash basis after recovery of principal is reasonably assured. Non-accrual loans are returned to accrual status when the financial position of the borrower and other relevant factors indicate that the Company will collect all principal and interest.

Commercial loans and loans secured by real estate are charged-off when deemed uncollectible. A loss is recorded if the net realizable value of the underlying collateral is less than the outstanding principal and interest. Consumer loans that are not secured by real estate are subject to mandatory charge-off at a specified delinquency date and are usually not classified as non-accrual prior to being charged-off. Closed-end consumer loans, which include installment, automobile, and single payment loans, are usually charged-off no later than the end of the month in which the loan becomes 120 days past due.

PCI loans are generally considered accruing loans unless reasonable estimates of the timing and amount of expected future cash flows cannot be determined. Loans without reasonable future cash flow estimates are classified as non-accrual loans, and interest income is not recognized on those loans until the timing and amount of the expected future cash flows can be reasonably determined.

The Company does not accrue interest on a TDR unless it believes collection of all principal and interest under the modified terms is reasonably assured. For a TDR to begin accruing interest, the borrower must demonstrate some level of past performance and the future capacity to perform under the modified terms. Generally, six months of consecutive payment performance under the restructured terms is required before a TDR is returned to accrual status. However, the period could vary depending on the individual facts and circumstances of the loan. An evaluation of the borrower's current creditworthiness is used to assess the borrower's capacity to repay the loan under the modified terms. This evaluation includes an estimate of expected future cash flows, evidence of strong financial position, and estimates of the value of collateral, if applicable. For TDRs to be removed from TDR status in the calendar year after the restructuring, the loans must (i) have an interest rate and terms that reflect market conditions at the time of restructuring, and (ii) be in compliance with the modified terms. If the loan was restructured at below market rates and terms, it continues to be separately reported as restructured until it is paid in full or charged-off.

The value of collateral-dependent loans is based on the fair value of the underlying collateral, less costs to sell. The value of other loans is measured using the present value of expected future cash flows discounted at the loan's initial effective interest rate.

Loans deemed to be uncollectible are charged-off against the allowance for loan losses, while recoveries of amounts previously charged-off are credited to the allowance for loan losses. Additions to the allowance for loan losses are charged to expense through the provision for loan losses. The amount of provision depends on a number of factors, including net charge-off levels, loan growth, changes in the composition of the loan portfolio, and the Company's assessment of the allowance for loan losses based on the methodology discussed below.

Allowance for Loan Losses – The allowance for loan losses consists of (i) specific reserves for individual loans where the recorded investment exceeds the value, (ii) an allowance based on a loss migration analysis that uses historical credit loss experience for each loan category, and (iii) an allowance based on other internal and external qualitative factors.

The specific reserves component of the allowance for loan losses is based on a periodic analysis of impaired loans exceeding a fixed dollar amount. If the value of an impaired loan is less than the recorded book value, the Company either establishes a valuation allowance (i.e., a specific reserve) equal to the excess of the book value over the collateral value of the loan as a component of the allowance for loan losses or charges off the amount if it is a confirmed loss.

The general reserve component is based on a loss migration analysis, which examines actual loss experience by loan category for a rolling 8-quarter period and the related internal risk rating for corporate loans. The loss migration analysis is updated quarterly primarily using actual loss experience. This component is then adjusted based on management's consideration of many internal and external qualitative factors, including:

The allowance for loan losses also consists of an allowance on acquired and covered non-PCI and PCI loans. No allowance for loan losses is recorded on acquired loans at the acquisition date. Subsequent to the acquisition date, an allowance for credit losses is established as necessary to reflect credit deterioration. The acquired non-PCI allowance is based on management's evaluation of the acquired non-PCI loan portfolio giving consideration to the current portfolio balance including the remaining acquisition adjustments, maturity dates, and overall credit quality. The allowance for covered non-PCI loans is calculated in the same manner as the general reserve component based on a loss migration analysis as discussed above. The acquired and covered PCI allowance reflects the difference between the carrying value and the discounted expected future cash flows of the acquired and covered PCI loans. On a periodic basis, the adequacy of this allowance is determined through a re-estimation of expected future cash flows on all of the outstanding acquired and covered PCI loans using either a probability of default/loss given default ("PD/LGD") methodology or a specific review methodology. The PD/LGD model is a loss model that estimates expected future cash flows using a probability of default curve and loss given default estimates. Acquired non-PCI loans that have renewed subsequent to the respective acquisition dates are no longer classified as acquired loans. Instead, they are included in the general loan population and allocated an allowance based on a loss migration analysis.

Reserve for Unfunded Commitments – The Company also maintains a reserve for unfunded commitments, including letters of credit, for the risk of loss inherent in these arrangements. The reserve for unfunded commitments is estimated using the loss migration analysis from the allowance for loan losses, adjusted for probabilities of future funding requirements. The reserve for unfunded commitments is included in other liabilities in the Consolidated Statements of Financial Condition.

The establishment of the allowance for credit losses involves a high degree of judgment given the difficulty of assessing the factors impacting loan repayment and estimating the timing and amount of losses. While management utilizes its best judgment and

information available, the adequacy of the allowance for credit losses depends on a variety of factors beyond the Company's control, including the performance of its loan portfolio, the economy, changes in interest rates and property values, and the interpretation of loan risk classifications by regulatory authorities.

On the date the Company enters into a derivative contract, the derivative is designated as a fair value hedge, a cash flow hedge, or a non-hedge derivative instrument. Fair value hedges are designed to mitigate exposure to changes in the fair value of an asset or liability attributable to a particular risk, such as interest rate risk. Cash flow hedges are designed to mitigate exposure to variability in expected future cash flows to be received or paid related to an asset, liability, or other type of forecasted transaction. The Company formally documents all relationships between hedging instruments and hedged items, including its risk management objective and strategy at inception.

At the hedge's inception, and quarterly thereafter, a formal assessment is performed to determine the effectiveness of the derivative in offsetting changes in the fair values or expected future cash flows of the hedged items in the current period and prospectively. If a derivative instrument designated as a hedge is terminated or ceases to be highly effective, hedge accounting is discontinued prospectively, and the gain or loss is amortized into earnings. For fair value hedges, the gain or loss is amortized over the remaining life of the hedged asset or liability. For cash flow hedges, the gain or loss is amortized over the same period that the forecasted hedged transactions impact earnings. If the hedged item is disposed of, any fair value adjustments are included in the gain or loss from the disposition of the hedged item. If the forecasted transaction is no longer probable, the gain or loss is included in earnings immediately.

For fair value hedges, changes in the fair value of the derivative instruments, as well as changes in the fair value of the hedged item, are recognized in earnings.earnings in the same income statement line item as the earnings effect of the hedged item. For cash flow hedges, the effective portion of the change in fair value of the derivative instrument is reported as a component of accumulated other comprehensive loss and is reclassified to earnings when the hedged transaction is reflected in earnings.

The Company's revenue is comprised of net interest income on financial assets and liabilities, which areis excluded from the scope of this guidance, and noninterest income. The Company expects that this guidance will change howprimary sources of revenue from certain revenue streams is recognized within noninterest income are service charges on deposit accounts, wealth management fees, but does not expect these changes to have a significant impact on the Company's financial condition, resultscard-based fees, and merchant servicing fees. The adoption of operations, or liquidity. The Company continues to evaluate the impact of this guidance on other components of noninterest income. The Company will adopt this guidance on January 1, 2018, using the modified retrospective approach, withaffected how the Company presents merchant servicing fees, merchant card expenses, card-based fees, and cardholder expenses, which are presented on a gross basis within noninterest income and noninterest expense for the prior period and are presented on a net basis within noninterest income for the current period. Total expenses of $3.7 million for the quarter ended March 31, 2018 were netted in noninterest income. The adoption of this guidance did not impact net income, therefore, a cumulative effect adjustment to opening retained earnings ifwas not deemed necessary. Consistent with the modified retrospective approach, the Company did not adjust prior period amounts for the reclassification of merchant card expenses and cardholder expenses.

During 2016, the CompanyFirst Midwest Bank (the "Bank") entered into a sale-leaseback transaction that resulted in a deferred gain of $82.5 million, with $78.1$73.1 million remaining as of June 30, 2017.March 31, 2018. Upon adoption of this guidance, the remaining deferred gain will be recognized immediately

On January 6, 2017, the Company completed theits acquisition of Standard Bancshares, Inc. ("Standard"), the holding company for Standard Bank and Trust Company. Pursuant to the terms of the merger agreement, on January 6, 2017, each outstanding share of Standard common stock was canceled and converted into the right to receive 0.4350 of a share of Company common stock. Based on the closing trading price of shares of Company common stock on the NASDAQof $25.34 on that date, of $25.34,as reported by NASDAQ, the value of the merger consideration per share of Standard common stock was $11.02. Each outstanding Standard stock settled right was redeemed for cash, and each outstanding Standard stock option and each share of Standard phantom stock was canceled and terminated in exchange for the right to receive cash, in each case, pursuant to the terms of the merger agreement. This resulted in an overall transaction value of approximately $580.7 million, which consisted of 21,057,085 shares of Company common stock and $47.1 million in cash. Goodwill of $339.3$345.3 million associated with the acquisition was recorded by the Company. All operating systems were converted during the first quarter of 2017.

During the second quarter of 2017, the Company updatedfinalized the fair value adjustments associated with the Standard transaction. The adjustments were recognized in the current period in accordance with accounting guidance applicable to business combinations. The fair value adjustments, including goodwill, remain preliminary and may change as the Company continues to finalize the fair value of the assets and liabilities acquired.transactions.

On February 28, 2017, the Company completed theits acquisition of Premier Asset Management LLC ("Premier"), a registered investment advisor based in Chicago, Illinois. At the close of the acquisition, the Company acquired approximately $550.0 million of trust assets under management. The fair value adjustments, including goodwill, remain preliminary and may change as

During the first quarter of 2018, the Company continues to finalizefinalized the fair value of the assets and liabilities acquired.

The significant accounting policies related to securities are presented in Note 1, "Summary of Significant Accounting Policies" to the Consolidated Financial Statements in the Company's 20162017 10-K.

A summary of the Company's securities portfolio by category and maturity is presented in the following tables.

The carrying value of securities available-for-sale that were pledged to secure deposits or for other purposes as permitted or required by law totaled $1.0 billion for March 31, 2018 and $1.1 billion for both June 30, 2017 and December 31, 2016.2017. No securities held-to-maturity were pledged as of June 30, 2017March 31, 2018 or December 31, 2016.2017.

During the quarters ended March 31, 2018 and six months ended June 30, 2017 and 2016 there were no material gross trading gains (losses). The following table presents net and there were no realized gains (losses) on securities available-for-sale for the quarters and six months ended June 30, 2017 and 2016.

Accounting guidance requires that the credit portion of an OTTIother-than-temporary impairment ("OTTI") charge be recognized through income. If a decline in fair value below carrying value is not attributable to credit deterioration and the Company does not intend to sell the security or believe it would not be more likely than not required to sell the security prior to recovery, the Company records the non-credit related portion of the decline in fair value in other comprehensive income.

The following table presents the aggregate amount of unrealized losses and the aggregate related fair values of securities with unrealized losses as of June 30, 2017March 31, 2018 and December 31, 2016.2017.