SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 10-Q

(Mark One)

For the quarterly period ended March 31, 20122013

OR

For the transition period from            To                    

Commission file number 0-12508

S&T BANCORP, INC.

(Exact name of registrant as specified in its charter)

800-325-2265

(Registrant’s telephone number, including area code)

Not Applicable

(Former name, former address, and former fiscal year, if changed since last report)

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 (Section 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, or a smaller reporting company. See the definition of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ¨ No x

APPLICABLE ONLY TO CORPORATE ISSUERS:

Indicate the number of shares outstanding of each of the issuer’s classes of common stock, as of the latest practical date.

Common Stock, $2.50 Par Value - 28,913,22029,720,105 shares as of April 30, 201222, 2013

INDEX

S&T BANCORP, INC. AND SUBSIDIARIES

S&T BANCORP, INC. AND SUBSIDIARIES

CONSOLIDATED BALANCE SHEETS

See Notes to Consolidated Financial Statements

S&T BANCORP, INC. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME

(Unaudited)

See Notes to Consolidated Financial Statements

S&T BANCORP, INC. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS’ EQUITY

(Unaudited)

See Notes to Consolidated Financial Statements

S&T BANCORP, INC. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF CASH FLOWS

(Unaudited)

⁽¹⁾There were no taxes paid during either of the quarters presented above due to the carry forward of prior year overpayments.

See Notes to Consolidated Financial Statements

S&T BANCORP, INC. AND SUBSIDIARIES

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

NOTE 1. BASIS OF PRESENTATION

Principals of Consolidation

The interim Consolidated Financial Statements include the accounts of S&T Bancorp, Inc., or 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, or 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, 2011,2012, filed with the SEC on February 28, 2012.25, 2013. 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.

Reclassification

Certain amounts in the prior periods’ financial statements and footnotes have been reclassified to conform to the current period’s presentation. The reclassifications had no significant effect on our results of operations or financial condition.

Use of Estimates

The preparation of financial statements in conformity with U.S. generally accepted accounting principlesGAAP 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

PresentationReporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income

In December 2011,February 2013, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU No. 2011-12, which supersedes certain pending paragraphs in2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income. ASU No. 2011-05. It effectively defers changes that relate to2013-02 requires reporting the presentationeffect of reclassification adjustments out of accumulated other comprehensive income. The amendments will be temporary to allow the FASB time to redeliberate the presentation requirements forsignificant reclassifications out of accumulated other comprehensive income for annual and interimby component on the respective line items in the income statement parenthetically or in the notes to the financial statements.statements if the amounts being reclassified are required under U.S. GAAP to be reclassified in their entirety to net income. This amendment is effective at the same time as the amendments in ASU No. 2011-05. It should be applied retrospectively and is effective for public companies prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2011.2012 and early adoption is permitted. We have elected the option of reporting in the notes to the financial statements. The adoption of this ASU has2013-02 impacted only impacted our presentation of comprehensive incomedisclosures and hasdid not hadhave an impact on our results of operations or financial position.

Testing Goodwill for ImpairmentClarifying the Scope of Disclosures about Offsetting Assets and Liabilities

In September 2011,January 2013, the FASB issued ASU No. 2011-08, which permits2013-01, Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities in order to clarify the scope of ASU 2011-11, Disclosures About Offsetting Assets and Liabilities, issued in December 2011. ASU 2011-11 required entities to disclose both gross and net information about instruments and transactions eligible for offset in the statement of financial position and instruments and transactions subject to an entityagreement similar 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 that its fair value is less than its carrying amount, it need not perform the two-step impairment test.master netting arrangement. This ASU iswas issued to allow investors to better compare financial statements prepared under U.S. GAAP with financial statements prepared under International Financial Reporting Standards, or IFRS. ASU 2013-01 clarified that ASU 2011-11 applies to derivatives, sale and repurchase agreements and reverse sale of repurchase agreements, and securities borrowing and securities lending arrangements, but does not apply to standard commercial contracts allowing either party to net in the event of default or to broker-dealer unsettled regular-way trades. Both ASUs are effective for annual and interim goodwill impairment tests performedpublic companies retrospectively for fiscal years, and interim periods within those years, beginning on or after December 15, 2011. Early adoption is permitted.January 1, 2013. The adoption of this ASU has2013-02 and ASU 2011-11 impacted only our disclosures and did not had a materialhave an impact on our results of operations or financial position.

S&T BANCORP, INC. AND SUBSIDIARIES

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued

NOTE 1. BASIS OF PRESENTATION– continued

Recently Issued Accounting Standards Updates not yet Adopted

PresentationObligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of Comprehensive Incomethe Obligation is Fixed at the Reporting Date

In June 2011,February 2013, the FASB issued ASU No. 2011-05,2013-04, Obligations Resulting from Joint and Several Liability Arrangements for Which the provisionsTotal Amount of which allow an entity the option to presentObligation is Fixed at the Reporting Date. The ASU requires the measurement of obligations resulting from joint and several liability arrangements for which 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 statementobligation is fixed at the reporting date as the sum of changes in stockholders’ equity. ASU 2011-05 does not change the itemsamount the reporting entity agreed to pay on the basis of its arrangement with its co-obligors as well as any additional amount that must be reported in other comprehensive income or when an itemthe entity expects to pay on behalf of other comprehensive income must be reclassified to net income. ASU 2011-05 permits companies to present in the annual period the comprehensive income components in a single continuous statement or two consecutive statements and to present in the interim periods only the total for comprehensive income in a single continuous statement or two consecutive statements. We have elected this option in a single continuous statement format for interim periods. ASU 2011-05 should be applied retrospectively andits co-obligors. The new standard is effective for public companiesretrospectively for fiscal years and interim periods within those years, beginning after December 15, 2011. The adoption of this ASU has only impacted our presentation of comprehensive income2013, and has not had an impact on our results of operations or financial position.

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

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 U.S. GAAP or IFRS. For U.S. GAAP, most of the changes are clarifications of existing guidance or wording changes to align with IFRS 13 Fair Value Measurement. A public company is required to apply the ASU prospectively for interim and annual periods beginning after December 15, 2011. Earlyearly adoption is not permitted for a public company. The adoptionpermitted. We are currently evaluating the implications of this ASU has impacted only disclosure requirements and did not have a material impact on our results of operations or financial position.2013-04.

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, or 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 had no impact on our results of operations or financial position.

Recently Issued Accounting Standards Updates not yet Adopted

Disclosures About Offsetting Assets and Liabilities

In December 2011, the FASB issued ASU No. 2011-11, in conjunction with the IASB’s issuance of amendments to Disclosures—Offsetting Financial Assets and Financial Liabilities (Amendments to IFRS 7). The disclosure requirements apply to recognized financial instruments and derivative instruments that are offset or subject to an enforceable master netting arrangement. An entity shall disclose information to enable users of its financial statements to evaluate the effect or potential effect of netting arrangements on its financial position, including the effect or potential effect of rights of setoff associated with recognized assets and recognized liabilities. While both the FASB and the IASB retained the existing offsetting models under U.S. GAAP and IFRS, the new standards require disclosures to allow investors to better compare financial statements prepared under U.S. GAAP with financial statements prepared under IFRS. The new standards are effective for annual periods beginning January 1, 2013, and interim periods within those annual periods. Retrospective application is required. The adoption of this ASU is not expected to have a material impact on our results of operations or financial position.

S&T BANCORP, INC. AND SUBSIDIARIES

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued

NOTE 2. BUSINESS COMBINATION

On March 9, 2012, we completed the acquisition of 100 percent of the voting shares of Mainline Bancorp, Inc., or Mainline, located in Ebensburg, Pennsylvania, which was the sole shareholder of Mainline National Bank, in a nontaxable stock and cash transaction. The acquisition expanded our market share and footprint throughout Cambria and Blair Counties of Western Pennsylvania. Mainline shareholders were entitled to elect to receive for each share of Mainline common stock either $69.00 in cash or 3.6316 shares of S&T common stock. We paid $8.5 million in cash and issued 673,275 common shares at a fair value of $21.42 per share or $14.4 million to the former Mainline shareholders. The fair value of $21.42 per share of S&T common stock was based on the March 9, 2012 closing price. We also purchased Mainline’s preferred stock issued under the U.S. Treasury Capital Purchase Program, or CPP, for $4.7 million on March 9, 2012. The preferred stock was purchased and retired as part of the merger transaction.

The acquisition was accounted for under the acquisition method of accounting, and all transactions of Mainline since the acquisition date are included in our consolidated financial statements. The assets acquired and liabilities assumed were recorded at their respective fair values and represent management’s estimates based on available information.

Goodwill of $6.1 million was calculated as the excess of the consideration exchanged over the net identifiable assets acquired. The goodwill arising from the acquisition consists largely of the synergies and economies of scale expected from combining the operations of S&T and Mainline. All of the goodwill was assigned to our Community Banking segment. The goodwill recognized will not be deductible for tax purposes.

The following table summarizes total consideration, assets acquired and liabilities assumed at March 9, 2012:

Provisional amounts have been recorded for the fair values of loans, deposits and the core deposit intangible at March 31, 2012. Additional adjustments will be required to finalize the acquisition accounting for Mainline since only preliminary valuations were available at the time of this filing. The measurement period for the Mainline acquisition ends March 9, 2013.

Loans acquired in the Mainline acquisition were recorded at fair value with no carryover of the related allowance for loan losses. Determining the fair value of the loans involves estimating the amount and timing of principal and interest cash flows expected to be collected on the loans and discounting those cash flows at a market rate of interest. Loans acquired with evidence of credit quality deterioration were not significant. We acquired $132.3 million of gross loans and recognized a net combined yield and credit mark of $3.0 million.

Direct costs related to the Mainline acquisition were expensed as incurred. During the first quarter 2012, we recognized $3.9 million of one-time merger related expenses, including $1.6 million in data processing contract termination and conversion costs, $1.7 million in change of control and severance payments and $0.4 million in legal and professional expenses.

S&T BANCORP, INC. AND SUBSIDIARIES

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued

NOTE 3.2. EARNINGS PER SHARE

The following table reconciles the numerators and denominators of basic earnings per share with that of diluted earnings per share for the periods presented:

NOTE 4.3. FAIR VALUE MEASUREMENTS

We use fair value measurements when recording and disclosing certain financial assets and liabilities. Securities available-for-sale, trading assets and derivatives are recorded at fair value on a recurring basis. Additionally, from time to time, we 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, or OREO, mortgage servicing rights, or MSRs, and certain other assets.

S&T BANCORP, INC. AND SUBSIDIARIES

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued

NOTE 3. FAIR VALUE MEASUREMENTS – continued

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, we use 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 areis developed, based on market data we have obtained from independent sources. Unobservable inputs reflect our 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.

S&T BANCORP, INC. AND SUBSIDIARIES

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued

NOTE 4. FAIR VALUE MEASUREMENTS – continued

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. Our 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 we use 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.

We obtain 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 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 inas 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

We use quoted market prices to determine the fair value of our trading assets. Our trading assets are held in a Rabbi Trust under a deferred compensation plan and are invested in readily quoted mutual funds. Accordingly, these assets are classified as Level 1. Trading assets are recorded in other assets in the Consolidated Balance Sheets.

Derivative Financial Instruments

We use derivative instruments including interest rate swaps for commercial loans with our customers and we sell mortgage loans in the secondary market and enter into interest rate lock commitments. We calculate 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.

We incorporate credit valuation adjustments into the valuation models to appropriately reflect both itsour own nonperformance risk and the respective counterparty’s nonperformance risk in calculating fair value measurements. In adjusting the fair value of our derivative contracts for the effect of nonperformance risk, we have considered the impact of netting and any applicable credit enhancements and collateral postings.

S&T BANCORP, INC. AND SUBSIDIARIES

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued

NOTE 3. FAIR VALUE MEASUREMENTS – continued

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 principal or most advantageous market currently offered 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 2.3.

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. We establish a specific reserve based on the following three impairment methods: 1) the present value of expected future cash flows discounted at the loan’s original 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 and we expect to liquidate.liquidate the collateral. However, if repayment is expected to come from the operation of the collateral, rather than liquidation, then we do not consider estimated selling costs in determining the fair value of the collateral. Collateral values are generally based upon appraisals by approved, independent state certified appraisers.

S&T BANCORP, INC. AND SUBSIDIARIES

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued

NOTE 4. FAIR VALUE MEASUREMENTS – continued

Appraisals may be discounted based on our historical knowledge, changes in market conditions from the time of valuationappraisal or our knowledge of the borrower and the borrower’s business. Impaired loans carried at fair value are classified as Level 3.

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 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 our historical knowledge, changes in market conditions from the time of valuationappraisal or other information available to us. OREO and other repossessed assets are classified as Level 3.

Mortgage Servicing Rights

The fair value of MSRs 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 MSRs. If the carrying value of MSRs exceeds fair value, they are considered impaired. As the valuation model includes significant unobservable inputs, MSRs are classified as Level 3 within the fair value hierarchy.

Other Assets

In accordance with GAAP, weWe measure 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 downswrite-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 our 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 our assets and liabilities are considered financial instruments as defined in the guidance.instruments. 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 our general practice and intent to hold our financial instruments to maturity and to not engage in trading or sales activities.activities with respect to such financial instruments. For fair value disclosure purposes, we substantially utilizedutilize the fair value measurement criteria as required and explained above. In cases where quoted fair values are not available, we use present value methods to determine the fair value of our 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, including interest-bearing deposits, approximate fair value.

S&T BANCORP, INC. AND SUBSIDIARIES

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued

NOTE 4.3. FAIR VALUE MEASUREMENTS – continued

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 fair value.

Short-Term Borrowings

The carrying amounts of securities sold under repurchase agreements, federal funds purchased 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 are not made because of the short-term nature of these arrangements and the credit standing of the counterparties.

Other

Estimates of fair value are not made for items that are not defined as financial instruments, including such items as our core deposit intangibles and the value of our trust operation.operations.

S&T BANCORP, INC. AND SUBSIDIARIES

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued

NOTE 4.3. FAIR VALUE MEASUREMENTS – continued

The following tables present our assets and liabilities that are measured at fair value on a recurring basis by fair value hierarchy level at March 31, 20122013 and December 31, 2011.2012. There were no transfers between Level 1 and Level 2 for items measured at fair value on a recurring basis during the periods presented.