NOTE 1. BASIS OF PRESENTATION

Principals of Consolidation

The interim Consolidated Financial Statements include the accounts of S&T Bancorp, Inc. and subsidiaries ("S&T") and its wholly owned subsidiaries. All significant intercompany transactions have been eliminated in consolidation. Investments of 20 percent to 50 percent of the outstanding common stock of investees are accounted for using the equity method of accounting.

Basis of Presentation

The accompanying unaudited interim Consolidated Financial Statements of S&T have been prepared in accordance with generally accepted accounting principles ("GAAP") in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with our annual report on Form 10-K for the year ended December 31, 2010, filed with the SEC on March 16, 2011. In the opinion of management, the accompanying interim financial information reflects all adjustments, including normal recurring adjustments, necessary to present fairly S&T's financial position and results of operations for each of the interim periods presented. Results of operations for interim periods are not necessarily indicative of the results of operations that may be expected for a full year or any future period.

Reclassifications

Certain prior period amounts have been reclassified to conform to the current year's presentation. These reclassifications did not have a material impact on S&T's consolidated financial condition or results of operations.

Acquisition of Mainline Bancorp, Inc.

On September 14, 2011, S&T announced the signing of a definitive merger agreement to acquire Mainline Bancorp, Inc. ("Mainline"), a bank holding company based in Ebensburg, Pennsylvania. Mainline, with approximately $242 million in assets, maintains eight offices in Cambria and Blair counties of Pennsylvania. Under the terms of the merger agreement, shareholders of Mainline will have the opportunity to elect to receive $69.00 per share in cash, or between 3.6316 and 4.3125 shares of S&T common stock, with the precise number of shares based on the average of the high and low sale prices of S&T for a 10 trading day period ending 5 days prior to the business day preceding the merger vote by Mainline shareholders. The transaction, valued at approximately $21 million, is expected to be completed in the first quarter of 2012, pending regulatory approvals, the approval of shareholders of Mainline, and other closing conditions.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates.

Recently Adopted Accounting Standards Updates

A Creditor's Determination of Whether a Restructuring Is a Troubled Debt Restructuring

In April 2011, the FASB issued ASU No. 2011-02, which amends the guidance for evaluating whether the restructuring of a receivable by a creditor is a troubled debt restructuring ("TDR"). In evaluating whether a restructuring constitutes a TDR both for purposes of recording an impairment loss and for disclosure purposes, a creditor must separately conclude that both of the following exist: (a) the restructuring constitutes a concession; and (b) the debtor is experiencing financial difficulties. For S&T, the new guidance was effective July 1, 2011, and applies retrospectively to restructurings occurring on or after January 1, 2011. S&T is also required to disclose the activity based information that was previously deferred by ASU No. 2011-01. The adoption of this ASU did not have a material impact on S&T's results of operations or financial position.

When to Perform Step 2 of the Goodwill Impairment Test for Reporting Units with Zero or Negative Carrying Amounts

In December 2010, the FASB issued ASU No. 2010-28, which reflects the decision reached in EITF Issue No. 10-A. This ASU modifies Step 1 of the goodwill impairment test for reporting units with zero or negative carrying amounts. For those reporting units, an entity is required to perform Step 2 of the goodwill impairment test if it is more likely than not that a goodwill impairment exists. In determining whether it is more likely than not that goodwill impairment exists, an entity should consider whether there are any adverse qualitative factors indicating that impairment may exist. The qualitative factors are consistent with the existing guidance and examples, which require that goodwill of a reporting unit be tested for impairment between annual tests if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. For public entities, this ASU was effective for fiscal years, and interim periods within those years, beginning after December 15, 2010. The adoption of this ASU did not have a material impact on S&T's results of operations or financial position.

Recently Issued Accounting Standards Updates

Testing Goodwill for Impairment

In September 2011, the FASB issued ASU No. 2011-08, which permits an entity to make a qualitative assessment of whether it is more likely than not that a reporting unit's fair value is less than its carrying amount before applying the two-step goodwill impairment test. If an entity concludes it is not more likely than not, it need not perform the two-step impairment test. This ASU is effective for annual and interim goodwill impairment tests performed for fiscal years beginning after December 15, 2011. Early adoption is permitted. The adoption of this ASU is not expected to have a material impact on S&T's results of operations or financial position.

Presentation of Comprehensive Income

In June 2011, the FASB issued ASU No. 2011-05, the provisions of which allow an entity the option to present the total of comprehensive income, the components of net income and the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements. Under both options, an entity is required to present each component of net income along with total net income, each component of other comprehensive income along with a total for other comprehensive income and a total amount for comprehensive income. ASU 2011-05 eliminates the option to present the components of other comprehensive income as part of the statement of changes in stockholders' equity. ASU 2011-05 does not change the items that must be reported in other comprehensive income or when an item of other comprehensive income must be reclassified to net income. ASU 2011-05 should be applied retrospectively and is effective for public companies for fiscal years, and interim periods within those years, beginning after December 15, 2011. The adoption of this ASU will only impact S&T's presentation of comprehensive income and is not expected to have an impact on S&T's results of operations or financial position.

Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRSs

In May 2011, the FASB issued ASU No. 2011-04, which represents the convergence of the FASB's and the IASB's guidance on fair value measurement. ASU 2011-04 reflects the common requirements under U.S. GAAP and IFRS for measuring fair value and for disclosing information about fair value measurements, including a consistent meaning for the term "fair value." The new guidance does not extend the use of fair value but, rather, provides guidance about how fair value should be applied where it is already required or permitted under IFRS or U.S. GAAP. For U.S. GAAP, most of the changes are clarifications of existing guidance or wording changes to align with IFRS 13. A public company is required to apply the ASU prospectively for interim and annual periods beginning after December 15, 2011. Early adoption is not permitted for a public company. The adoption of this ASU is not expected to have a material impact on S&T's results of operations or financial position.

Reconsideration of Effective Control for Repurchase Agreements

In April 2011, the FASB issued ASU No. 2011-03, which is intended to improve financial reporting of repurchase agreements ("repos") and other agreements that both entitle and obligate a transferor to repurchase or redeem financial assets before their maturity. When an entity enters into a typical repo arrangement, it transfers financial assets to a counterparty in exchange for cash with an agreement for the counterparty to return the same or equivalent financial assets for a fixed price in the future. Current guidance prescribes when an entity may or may not recognize a sale upon the transfer of financial assets subject to a repo agreement. That determination is based, in part, on whether the entity has maintained effective control over the transferred financial assets. This ASU improves the accounting for these transactions by removing from the assessment of effective control the criterion requiring the transferor to have the ability to repurchase or redeem the financial assets and focuses the assessment on the transferor's contractual rights. This guidance is effective for the first interim or annual period beginning on or after December 15, 2011. The guidance should be applied prospectively to transactions or modifications of existing transactions that occur on or after the effective date. Early adoption is not permitted. The adoption of this ASU is not expected to have a material impact on S&T's results of operations or financial position.

NOTE 2. CAPITAL PURCHASE PROGRAM

On January 16, 2009, S&T, as a participant in the U.S. Treasury Capital Purchase Program ("CPP"), issued to the U.S. Treasury 108,676 shares of its Series A Preferred Stock and a Warrant to purchase 517,012 shares of common stock at an exercise price of $31.53 per share, in exchange for proceeds of $108.7 million. The Series A Preferred Stock pays cumulative dividends at a rate of five percent per year for the first five years and thereafter at a rate of nine percent per year. The Warrant provides for the adjustment of the exercise price and the number of shares of S&T's common stock issuable upon exercise pursuant to customary anti-dilution provisions, such as upon stock splits or distributions of securities or other assets to holders of S&T's common stock and upon certain issuances of S&T's common stock at or below a specified price relative to the initial exercise price. The U.S. Treasury has agreed not to exercise voting power with respect to any shares of common stock issued upon exercise of the Warrant. The Warrant expires ten years from date of issuance.

Under changes made to the CPP by the American Recovery and Reinvestment Act of 2009 ("ARRA"), S&T can redeem the Series A Preferred Stock, plus any accrued and unpaid dividends, subject to approval by banking regulatory agencies, at any time. If S&T only redeems part of the CPP investment, then it must pay a minimum of 25 percent of the issuance price, or $27.2 million. The consent of the U.S. Treasury will be required for S&T to increase its common stock dividend (above the dividend amount prior to S&T's participation in the CPP) or repurchase its common stock or other equity or capital securities, other than in connection with benefit plans consistent with past practice and certain other circumstances through January 16, 2012. The consent of the U.S. Treasury will not be required if S&T has redeemed the Series A Preferred Stock or the U.S. Treasury has transferred the Series A Preferred Stock to a third party. In addition, the Series A Preferred Stock issuance includes certain restrictions on executive compensation that could limit the tax deductibility of compensation S&T pays to executive management.

NOTE 3. FAIR VALUE MEASUREMENTS

S&T uses fair value measurements to record fair value adjustments to certain financial assets and liabilities and to determine fair value disclosures. Securities available-for-sale, trading assets and derivatives are recorded at fair value on a recurring basis. Additionally, from time to time, S&T may be required to record other assets at fair value on a nonrecurring basis, such as loans held for sale, impaired loans, other real estate owned ("OREO"), mortgage servicing rights ("MSR") and certain other assets.

Fair value is the price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market in an orderly transaction between market participants at the measurement date. An orderly transaction is a transaction that assumes exposure to the market for a period prior to the measurement date to allow for marketing activities that are usual and customary for transactions involving such assets or liabilities; it is not a forced transaction. In determining fair value, S&T uses various valuation approaches, including market, income and cost approaches. The fair value standard establishes a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing an asset or liability, which are developed, based on market data obtained from sources independent of S&T. Unobservable inputs reflect S&T's estimate of assumptions that market participants would use in pricing an asset or liability, which are developed based on the best information available in the circumstances.

The fair value hierarchy gives the highest priority to unadjusted quoted market prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority to unobservable inputs (Level 3 measurement). The fair value hierarchy is broken down into three levels based on the reliability of inputs as follows:

Level 1: valuation is based upon unadjusted quoted market prices for identical instruments traded in active markets.

Level 2: valuation is based upon quoted market prices for similar instruments traded in active markets, quoted market prices for identical or similar instruments traded in markets that are not active and model-based valuation techniques for which all significant assumptions are observable in the market or can be corroborated by market data.

Level 3: valuation is derived from other valuation methodologies including discounted cash flow models and similar techniques that use significant assumptions not observable in the market. These unobservable assumptions reflect estimates of assumptions that market participants would use in determining fair value.

A financial instrument's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. S&T's policy is to recognize transfers between any of the fair value hierarchy levels at the end of the reporting period in which the transfer occurred.

The following are descriptions of the valuation methodologies that S&T uses for financial instruments recorded at fair value on either a recurring or nonrecurring basis.

Recurring Basis

Securities Available-for-Sale

Securities available-for-sale include both debt and equity securities.

S&T obtains estimated fair values for debt securities from a third-party pricing service, which utilizes several sources for valuing fixed-income securities. The market evaluation sources for debt securities include observable inputs rather than significant unobservable inputs and are classified as Level 2. The service provider utilizes evaluated pricing models that vary by asset class and include available trade, bid and other market information. Generally, the methodologies include broker quotes, proprietary models, vast descriptive terms and conditions databases, as well as extensive quality control programs.

Marketable equity securities that have an active, quotable market are classified in Level 1. Marketable equity securities that are quotable, but are thinly traded or inactive, are classified as Level 2 and securities that are not readily traded and do not have a quotable market are classified as Level 3.

Trading Assets

S&T uses quoted market prices to determine the fair value of its trading assets. S&T's trading assets are held in a Rabbi Trust under a deferred compensation plan and are invested in two readily quoted mutual funds. Accordingly, these assets are classified as Level 1.

Derivative Financial Instruments

S&T calculates the fair value for derivatives using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. Each valuation considers the contractual terms of the derivative, including the period to maturity and uses observable market based inputs, such as interest rate curves and implied volatilities. Accordingly, derivatives are classified as Level 2.

S&T incorporates credit valuation adjustments into the valuation models to appropriately reflect both its own nonperformance risk and the respective counterparty's nonperformance risk in calculating fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, S&T has considered the impact of netting and any applicable credit enhancements and collateral postings.

Nonrecurring Basis

Loans Held for Sale

Loans held for sale consist of 1-4 family residential loans originated for sale in the secondary market and from time to time, certain loans transferred from the loan portfolio to loans held for sale, all of which are carried at the lower of cost or fair value. The fair value of 1-4 family residential loans is based on the price secondary markets are currently offering for similar loans using observable market data. The fair value of the loans transferred from the loan portfolio is based on the amounts offered for these loans in currently pending sales transactions. Loans held for sale carried at fair value are classified as Level 2.

Impaired Loans

Impaired loans are carried at the lower of carrying value or fair value. Fair value is determined as the recorded investment balance less any specific reserve. S&T establishes a specific reserve based on the following three impairment methods: 1) the present value of expected future cash flows discounted at the loan's effective interest rate, 2) the loan's observable market price or 3) the fair value of the collateral less estimated selling costs when the loan is collateral dependent. Collateral values are generally based upon appraisals by approved, independent state certified appraisers.

Appraisals may be discounted based on management's historical knowledge, changes in market conditions from the time of valuation or management's knowledge of the borrower and the borrower's business. Because not all valuation inputs are observable, impaired loans are classified as Level 2 or Level 3 based on the lowest level of input that is significant to the fair value measurement.

OREO and Other Repossessed Assets

OREO and other repossessed assets obtained in partial or total satisfaction of a loan are recorded at the lower of recorded investment in the loan or fair value less cost to sell. Subsequent to foreclosure, these assets are carried at the lower of the amount recorded at acquisition date or estimated fair value less cost to sell. Accordingly, it may be necessary to record nonrecurring fair value adjustments. Fair value, when recorded, is generally based upon appraisals by approved, independent state certified appraisers. Like impaired loans, appraisals on OREO may be discounted based on management's historical knowledge, changes in market conditions from the time of valuation or other information available to management. Because not all valuation inputs are observable, OREO and other repossessed assets are classified as Level 2 or Level 3 based on the lowest level of input that is significant to the fair value measurement.

Mortgage Servicing Rights

The fair value of MSR is determined by calculating the present value of estimated future net servicing cash flows, considering expected mortgage loan prepayment rates, discount rates, servicing costs and other economic factors, which are determined based on current market conditions. The expected rate of mortgage loan prepayments is the most significant factor driving the value of MSR. If the carrying value of MSR exceeds fair value, they are considered impaired. As the valuation model includes significant unobservable inputs, MSR are classified as Level 3 within the fair value hierarchy.

Other Assets

In accordance with GAAP, S&T measures certain other assets at fair value on a nonrecurring basis. Fair value is based on the application of lower of cost or fair value accounting, or write downs of individual assets. Valuation methodologies used to measure fair value are consistent with overall principles of fair value accounting and consistent with those described above.

Financial Instruments

In addition to financial instruments recorded at fair value in S&T's financial statements, fair value accounting guidance requires disclosure of the fair value of all of an entity's assets and liabilities that are considered financial instruments. The majority of S&T's assets and liabilities are considered financial instruments as defined in the guidance. Many of these instruments lack an available trading market as characterized by a willing buyer and willing seller engaged in an exchange transaction. Also, it is S&T's general practice and intent to hold its financial instruments to maturity and to not engage in trading or sales activities. For fair value disclosure purposes, S&T substantially utilized the fair value measurement criteria as required and explained above. In cases where quoted fair values are not available, S&T uses present value methods to determine the fair value of its financial instruments.

Cash and Cash Equivalents and Other Short-Term Assets

The carrying amounts reported in the Consolidated Balance Sheets for cash and due from banks and interest-bearing deposits with banks approximate fair value.

Loans

The fair value of variable rate performing loans is based on carrying values adjusted for credit risk. The fair value of fixed rate performing loans is estimated using discounted cash flow analyses, utilizing interest rates currently being offered for loans with similar terms, adjusted for credit risk. The fair value of nonperforming loans is based on their carrying values less any specific reserve. The carrying amount of accrued interest approximates fair value.

Bank Owned Life Insurance

Fair value approximates net cash surrender value.

Deposits

The fair values disclosed for deposits without defined maturities (e.g., noninterest and interest-bearing demand, money market and savings accounts) are by definition equal to the amounts payable on demand. The carrying amounts for variable rate, fixed-term time deposits approximate their fair values. Estimated fair values for fixed rate and other time deposits are based on discounted cash flow analysis, using interest rates currently offered for time deposits with similar terms. The carrying amount of accrued interest approximates its estimated fair value.

Short-Term Borrowings

The carrying amounts of federal funds purchased, securities sold under repurchase agreements and other short-term borrowings approximate their fair values.

Long-Term Borrowings

The fair values disclosed for fixed rate long-term borrowings are determined by discounting their contractual cash flows using current interest rates for long-term borrowings of similar remaining maturities. The carrying amounts of variable rate long-term borrowings approximate their fair values.

Junior Subordinated Debt Securities

The variable rate junior subordinated debt securities reprice quarterly and fair values are based on carrying values.

Loan Commitments and Standby Letters of Credit

Off-balance sheet financial instruments consist of commitments to extend credit and letters of credit. Except for interest rate lock commitments, estimates of the fair value of these off-balance sheet items were not made because of the short-term nature of these arrangements and the credit standing of the counterparties.

The following tables present assets and liabilities that are measured at fair value on a recurring basis by fair value hierarchy level at September 30, 2011 and December 31, 2010. There were no transfers between Level 1 and Level 2 during the periods presented.

The following table presents the changes in assets classified as Level 3 in the fair value hierarchy that are measured at fair value on a recurring basis using significant unobservable inputs.

Changes in the fair market value of available-for-sale securities are recorded in accumulated other comprehensive loss, while realized gains and losses from sales are recorded in securities (losses) gains, net in the Consolidated Statements of Income.

There were no purchases, sales, issuances, settlements, or transfers out of Level 3 financial instruments during the periods presented.

The following tables present assets that are measured at fair value on a nonrecurring basis by fair value hierarchy level. There were no liabilities measured at fair value on a nonrecurring basis during the periods presented.

In addition to financial instruments recorded at fair value in S&T's financial statements, fair value accounting guidance requires disclosure of fair value of all of an entity's assets and liabilities considered to be financial instruments. For fair value disclosure purposes, S&T substantially utilized the fair value measurement criteria as required and discussed above. These estimates of fair value are significantly affected by the assumptions made and, accordingly, do not necessarily indicate amounts that could be realized in a current market exchange. The following table presents the estimated fair value of financial instruments as of:

NOTE 4. DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES

Interest Rate Swaps

Interest rate swaps are contracts in which a series of interest rate flows (fixed and variable) are exchanged over a prescribed period. The notional amounts on which the interest payments are based are not exchanged. S&T utilizes interest rate swaps for commercial loans. These derivative positions relate to transactions in which S&T enters into an interest rate swap with a customer while at the same time entering into an offsetting interest rate swap with another financial institution. In connection with each transaction, S&T agrees to pay interest to the customer on a notional amount at a variable interest rate and receive interest from the customer on a same notional amount at a fixed rate. At the same time, S&T agrees to pay another financial institution the same fixed interest rate on the same notional amount and receive the same variable interest rate on the same notional amount. The transaction allows S&T's customer to effectively convert a variable rate loan to a fixed rate loan with S&T receiving a variable yield. These agreements could have floors or caps on the contracted interest rates.

Pursuant to S&T's agreements with various financial institutions, S&T may receive collateral or may be required to post collateral based upon mark-to-market positions. Beyond unsecured threshold levels, collateral in the form of cash or securities may be made available to counterparties of swap transactions. Based upon S&T's current positions and related future collateral requirements relating to them, S&T believes any affect on its cash flow or liquidity position to be immaterial. Derivatives contain an element of credit risk, the possibility that S&T will incur a loss because a counterparty, which may be a financial institution or a customer, fails to meet its contractual obligations. All derivative contracts with financial institutions may be executed only with counterparties approved by S&T's Asset and Liability Committee ("ALCO") and derivatives with customers may only be executed with customers within credit exposure limits. Interest rate swaps are considered derivatives, but are not accounted for using hedge accounting. As such, changes in the fair value of the derivatives are recorded in current earnings and included in other noninterest income in the Consolidated Statements of Income.

Interest Rate Lock Commitments and Forward Sale Contracts

In the normal course of business, S&T sells originated mortgage loans into the secondary mortgage loan market. S&T offers interest rate lock commitments to potential borrowers. Whenever a customer desires these products, a mortgage originator quotes a secondary market rate guaranteed for that day by the investor. The commitments are generally for 60 days and guarantee a specified interest rate for a loan if underwriting standards are met, but the commitment does not obligate the potential borrower to close on the loan. Accordingly, some commitments expire prior to becoming loans. However, if the borrower accepts the guaranteed rate, S&T can encounter pricing risk if interest rates increase significantly before the loan can be closed and sold. S&T may utilize forward sale contracts in order to mitigate this pricing risk. The rate lock is executed between the mortgagee and S&T, and generally these rate locks are bundled. A forward sale contract is then executed between S&T and the investor. Both the interest rate lock commitment bundle and the corresponding forward sale contract are considered derivatives, but are not accounted for using hedge accounting. As such, changes in the fair value of the derivatives during the commitment period are recorded in current earnings and included in mortgage banking in the Consolidated Statements of Income.

NOTE 5. SECURITIES AVAILABLE-FOR-SALE

The following tables present the amortized cost and fair value of available-for-sale securities for the periods shown: