CONTACT: Mark Kochvar Chief Financial Officer 724.465.4826 mark.kochvar@stbank.com stbancorp.com

FOR IMMEDIATE RELEASE        

S&T Bancorp, Inc. Announces Second Quarter 2021 Net Income

Indiana, Pa. - July 22, 2021 - S&T Bancorp, Inc. (S&T) (NASDAQ: STBA), the holding company for S&T Bank, with operations in five markets including Western Pennsylvania, Eastern Pennsylvania, Northeast Ohio, Central Ohio and Upstate New York, announced net income of $28.4 million, or $0.72 per diluted share, for the second quarter of 2021 compared to net income of $31.9 million, or $0.81 per diluted share, for the first quarter of 2021, and a net loss of ($33.1) million, or ($0.85) per diluted share, for the second quarter of 2020. A loss of $58.7 million was recognized during the second quarter of 2020 related to a customer fraud resulting from a check kiting scheme. This fraud loss reduced net income by $46.3 million, or $1.19 per diluted share, resulting in a net loss for the second quarter of 2020.

New Chief Executive Officer

Christopher J. McComish has been appointed as the company's chief executive officer, effective August 23, 2021. Chris McComish has over 30 years of financial service experience, providing executive leadership to consumer banking, commercial banking, and wealth management businesses. He has a strong track record of driving growth and transformation while enhancing both digital and human customer engagement. Most recently, Chris served as senior executive vice president of TCF Bank, leading all consumer banking lines of business as well as business banking and wealth management. Prior to TCF, he served as president and CEO of Scottrade Bank, the banking subsidiary of Scottrade Financial Services, Inc. In addition, he served as the head of personal banking and then as chief operating officer for personal and commercial banking at BMO Harris Bank. He began his career at Wachovia Bank, where he spent over 20 years in various regional and line of business leadership roles.

"I am honored to have the opportunity to partner with Chris to lead this great organization," said David Antolik, president and interim chief executive officer. "Chris's experience in executive leadership roles in banking combined with my 30 plus years of experience at S&T puts us in a position of strength to move our company forward."

Second Quarter of 2021 Highlights:

•Christopher McComish has been appointed as the chief executive officer, effective August 23, 2021.

•Return on average assets (ROA) of 1.21%, return on average equity (ROE) of 9.65%, return on average tangible equity (ROTE) (non-GAAP) of 14.41% and pre-tax pre-provision income to average assets (PTPP) (non-GAAP) of 1.61%.

•Net interest margin (FTE) (non-GAAP) decreased 31 basis points to 3.16% compared to 3.47% for the first quarter of 2021 primarily due to higher cash balances and a lower Paycheck Protection Program (PPP) contribution.

•Ex-PPP portfolio loans decreased $12.7 million and total portfolio loans decreased $175.8 million compared to March 31, 2021.

•Deposits increased $139.2 million to $8.0 billion at June 30, 2021 compared to March 31, 2021.

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S&T Earnings Release -2

•The allowance for credit losses to total portfolio loans was 1.56% at June 30, 2021 compared to 1.60% at March 31, 2021.

•S&T's Board of Directors declared a $0.28 per share dividend which was consistent with the $0.28 per share dividend declared in the same period in the prior year.

"We continue to see positive signs of a recovery across all of our markets," said David Antolik. "Customer activity has increased substantially and our loan pipeline exceeds pre-pandemic levels making us optimistic about our growth prospects for the second half of 2021."

Net Interest Income

Net interest income decreased $2.4 million to $68.3 million for the second quarter of 2021 compared to $70.7 million for the first quarter of 2021. The decrease in net interest income was primarily due to a lower contribution from PPP and lower average loan balances ex-PPP. The PPP contribution decreased $1.7 million to $4.1 million for the second quarter of 2021 compared to $5.8 million in the first quarter of 2021. Average portfolio loans ex-PPP decreased $123.1 million compared to the first quarter of 2021. Net interest margin on a fully taxable equivalent basis (NIM) (FTE) (non-GAAP) decreased 31 basis points to 3.16% compared to 3.47% in the prior quarter. The decline in NIM (FTE) (non-GAAP) was due to a higher average cash balance (18 basis points), a lower PPP contribution (8 basis points) and lower loan yields (7 basis points). Partially offsetting these declines were lower costing liabilities which increased NIM (FTE) (Non-GAAP) by 5 basis points.

Asset Quality

The provision for credit losses decreased $0.5 million to $2.6 million for the second quarter of 2021 compared to $3.1 million in the first quarter of 2021. Net loan charge-offs were $7.5 million for the second quarter of 2021 compared to $5.8 million in the first quarter of 2021. Total nonperforming loans decreased $22.6 million to $112.6 million, or 1.61% of total loans, at June 30, 2021 compared to $135.2 million, or 1.88% of total loans at March 31, 2021. The allowance for credit losses was 1.56% of total portfolio loans as of June 30, 2021 compared to 1.60% at March 31, 2021. The allowance for credit losses was 1.64% of total portfolio ex-PPP loans at June 30, 2021 compared to 1.72% at March 31, 2021.

Noninterest Income and Expense

Noninterest income decreased $1.8 million to $15.4 million in the second quarter of 2021 compared to

$17.2 million in the first quarter of 2021. Mortgage banking income decreased $2.6 million due to a lower volume of loans sold and a decrease in the mortgage servicing rights valuation. Debit and credit card fees were strong with a $0.6 million increase compared to the prior quarter.

Noninterest expense increased $0.2 million to $45.8 million for the second quarter of 2021 compared to $45.6 million in the first quarter of 2021. Salaries and employee benefits increased $1.2 million due to annual merit increases and higher incentives.

Financial Condition

Total assets increased $166.9 million to $9.5 billion at June 30, 2021 compared to $9.3 billion at March 31, 2021. Cash increased $313.8 million to $985.3 million at June 30, 2021 compared to March 31, 2021 due to PPP forgiveness and an increase in deposits as a result of stimulus programs. Total portfolio loans decreased

$175.8 million compared to March 31, 2021. PPP originations were $31.1 million and PPP forgiveness was $194.2 million during the second quarter of 2021. Loan activity continues to be impacted by the pandemic. Deposits increased $139.2 million with a favorable mix of higher deposits across all categories except certificates of deposits. S&T continues to maintain a strong capital position with all capital ratios above the well-capitalized thresholds of federal bank regulatory agencies.

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S&T Earnings Release -3

Dividend

The Board of Directors of S&T declared a $0.28 per share cash dividend on July 19, 2021. This is unchanged from the same period in the prior year. The dividend is payable August 19, 2021 to shareholders of record on August 5, 2021.

Conference Call

S&T will host its second quarter 2021 earnings conference call live over the Internet at 1:00 p.m. ET on Thursday, July 22, 2021. To access the webcast, go to S&T’s webpage at www.stbancorp.com and click on “Events & Presentations.” Select “2nd Quarter 2021 Earnings Conference Call” and follow the instructions. After the live presentation, the webcast will be archived on this website for at least 90 days. A replay of the call will also be available until July 29, 2021, by dialing 1.877.481.4010; the Conference ID is 41690.

About S&T Bancorp, Inc. and S&T Bank

S&T Bancorp, Inc. is a $9.5 billion bank holding company that is headquartered in Indiana, Pennsylvania and trades on the NASDAQ Global Select Market under the symbol STBA. Its principal subsidiary, S&T Bank was established in 1902 and operates in five markets including Western Pennsylvania, Eastern Pennsylvania, Northeast Ohio, Central Ohio, and Upstate New York. For more information visit stbancorp.com or stbank.com. Follow us on Facebook, Instagram, and LinkedIn.

This information contains or incorporates statements that we believe are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements generally relate to our financial condition, results of operations, plans, objectives, outlook for earnings, revenues, expenses, capital and liquidity levels and ratios, asset levels, asset quality, financial position, and other matters regarding or affecting S&T and its future business and operations. Forward-looking statements are typically identified by words or phrases such as “will likely result”, “expect”, “anticipate”, “estimate”, “forecast”, “project”, “intend”, “ believe”, “assume”, “strategy”, “trend”, “plan”, “outlook”, “outcome”, “continue”, “remain”, “potential”, “opportunity”, “comfortable”, “current”, “position”, “maintain”, “sustain”, “seek”, “achieve” and variations of such words and similar expressions, or future or conditional verbs such as will, would, should, could or may. Although we believe the assumptions upon which these forward-looking statements are based are reasonable, any of these assumptions could prove to be inaccurate and the forward-looking statements based on these assumptions could be incorrect. The matters discussed in these forward-looking statements are subject to various risks, uncertainties and other factors that could cause actual results and trends to differ materially from those made, projected, or implied in or by the forward-looking statements depending on a variety of uncertainties or other factors including, but not limited to: credit losses and the credit risk of our commercial and consumer loan products; changes in the level of charge-offs and changes in estimates of the adequacy of the allowance for credit losses; cyber-security concerns; rapid technological developments and changes; operational risks or risk management failures by us or critical third parties, including fraud risk; our ability to manage our reputational risks; sensitivity to the interest rate environment including a prolonged period of low interest rates, a rapid increase in interest rates or a change in the shape of the yield curve; a change in spreads on interest-earning assets and interest-bearing liabilities; the transition from LIBOR as a reference rate; regulatory supervision and oversight, including changes in regulatory capital requirements and our ability to address those requirements; unanticipated changes in our liquidity position; changes in accounting policies, practices, or guidance, for example, our adoption of CECL; legislation affecting the financial services industry as a whole, and S&T, in particular; the outcome of pending and future litigation and governmental proceedings; increasing price and product/service competition; the ability to continue to introduce competitive new products and services on a timely, cost-effective basis; managing our internal growth and acquisitions; the possibility that the anticipated benefits from acquisitions, including DNB, cannot be fully realized in a timely manner or at all, or that integrating the acquired operations will be more difficult, disruptive or costly than anticipated; containing costs and expenses; reliance on significant customer relationships; an interruption or cessation of an important service by a third-party provider;

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S&T Earnings Release -4

our ability to attract and retain talented executives and employees; our ability to successfully manage our CEO transition; general economic or business conditions, including the strength of regional economic conditions in our market area; the duration and severity of the coronavirus (“COVID-19”) pandemic, both in our principal area of operations and nationally, including the ultimate impact of the pandemic on the economy generally and on our operations; our participation in the Paycheck Protection Program; deterioration of the housing market and reduced demand for mortgages; deterioration in the overall macroeconomic conditions or the state of the banking industry that could warrant further analysis of the carrying value of goodwill and could result in an adjustment to its carrying value resulting in a non-cash charge to net income; the stability of our core deposit base and access to contingency funding; re-emergence of turbulence in significant portions of the global financial and real estate markets that could impact our performance, both directly, by affecting our revenues and the value of our assets and liabilities, and indirectly, by affecting the economy generally and access to capital in the amounts, at the times and on the terms required to support our future businesses.

Many of these factors, as well as other factors, are described in our Annual Report on Form 10-K for the year ended December 31, 2020, including Part I, Item 1A-"Risk Factors" and any of our subsequent filings with the SEC. Forward-looking statements are based on beliefs and assumptions using information available at the time the statements are made. We caution you not to unduly rely on forward-looking statements because the assumptions, beliefs, expectations and projections about future events may, and often do, differ materially from actual results. Any forward-looking statement speaks only as to the date on which it is made, and we undertake no obligation to update any forward-looking statement to reflect developments occurring after the statement is made.

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S&T Bancorp, Inc.
Consolidated Selected Financial Data
Unaudited S&T Earnings Release - 5

			2021						2021						2020
			Second						First						Second
(dollars in thousands, except per share data)			Quarter						Quarter						Quarter
INTEREST AND DIVIDEND INCOME
Loans, including fees			$66,942						$70,232						$75,498
Investment Securities:
Taxable			3,793						3,563						3,791
Tax-exempt			690						813						959
Dividends			152						173						231
Total Interest and Dividend Income			71,577						74,781						80,479
INTEREST EXPENSE
Deposits			2,652						3,481						9,227
Borrowings and junior subordinated debt securities			621						641						1,104
Total Interest Expense			3,273						4,122						10,331
NET INTEREST INCOME			68,304						70,659						70,148
Provision for credit losses			2,561						3,137						86,759
Net Interest Income After Provision for Credit Losses			65,743						67,522						(16,611)
NONINTEREST INCOME
Net gain on sale of securities			29						—						142
Debit and credit card			4,744						4,162						3,612
Service charges on deposit accounts			3,642						3,474						2,805
Wealth management			3,167						2,944						2,585
Mortgage banking			1,734						4,310						2,623
Commercial loan swap income			299						95						945
Other			1,809						2,251						2,511
Total Noninterest Income			15,424						17,236						15,224
NONINTEREST EXPENSE
Salaries and employee benefits			24,515						23,327						21,419
Data processing and information technology			3,787						4,225						3,585
Occupancy			3,434						3,827						3,437
Furniture, equipment and software			2,402						2,640						3,006
Other taxes			1,832						1,436						1,604
Professional services and legal			1,637						1,531						1,932
Marketing			996						1,322						979
FDIC insurance			924						1,046						1,048
Other			6,302						6,226						6,468
Total Noninterest Expense			45,829						45,580						43,478
Income (Loss) Before Taxes			35,338						39,178						(44,865)
Income tax expense (benefit)			6,971						7,276						(11,793)
Net Income (Loss)			$28,367						$31,902						($33,072)
Per Share Data
Shares outstanding at end of period			39,345,719						39,268,359						39,263,460
Average shares outstanding - diluted			39,048,971						39,021,208						39,013,161
Diluted earnings (loss) per share			$0.72						$0.81						($0.85)
Dividends declared per share			$0.28						$0.28						$0.28
Dividend yield (annualized)			3.58		%				3.34		%				4.78		%
Dividends paid to net income			38.74		%				34.40		%				NM
Book value			$30.21						$29.75						$28.93
Tangible book value (1)			$20.57						$20.08						$19.22
Market value			$31.30						$33.50						$23.45
Profitability Ratios (Annualized)
Return on average assets			1.21		%				1.42		%				(1.41		%)
Return on average shareholders' equity			9.65		%				11.15		%				(11.17		%)
Return on average tangible shareholders' equity (2)			14.41		%				16.78		%				(16.19		%)
Pre-tax pre-provision income / average assets(3)			1.61		%				1.89		%				1.79		%
Efficiency ratio (FTE) (4)			54.37		%				51.47		%				50.51		%
NM - Not Meaningful

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S&T Bancorp, Inc.
Consolidated Selected Financial Data
Unaudited S&T Earnings Release - 6

									Six Months Ended June 30,
(dollars in thousands, except per share data)									2021						2020
INTEREST AND DIVIDEND INCOME
Loans, including fees									$137,174						$157,549
Investment Securities:
Taxable									7,356						8,074
Tax-exempt									1,503						1,762
Dividends									325						684
Total Interest and Dividend Income									146,358						168,069
INTEREST EXPENSE
Deposits									6,133						24,565
Borrowings and junior subordinated debt securities									1,263						3,320
Total Interest Expense									7,396						27,885
NET INTEREST INCOME									138,962						140,184
Provision for credit losses									5,699						106,809
Net Interest Income After Provision for Credit Losses									133,263						33,375
NONINTEREST INCOME
Net gain on sale of securities									29						142
Debit and credit card									8,906						3,859
Service charges on deposit accounts									7,116						6,814
Wealth management									6,111						4,949
Mortgage banking									6,044						7,093
Commercial loan swap income									393						3,429
Other									4,062						1,341
Total Noninterest Income									32,661						27,627
NONINTEREST EXPENSE
Salaries and employee benefits									47,842						42,754
Data processing and information technology									8,012						7,453
Occupancy									7,261						7,202
Furniture, equipment and software									5,042						5,525
Other taxes									3,268						3,205
Professional services and legal									3,168						2,980
Marketing									2,318						2,090
FDIC insurance									1,970						1,818
Merger related expenses									—						2,342
Other									12,528						14,500
Total Noninterest Expense									91,409						89,869
Income (Loss) Before Taxes									74,515						(28,867)
Income tax expense (benefit)									14,247						(9,026)
Net Income (Loss)									$60,268						($19,841)
Per Share Data
Average shares outstanding - diluted									39,034,808						39,142,351
Diluted earnings (loss) per share									$1.54						($0.51)
Dividends declared per share									$0.56						$0.56
Dividends paid to net income									36.44%						NM
Profitability Ratios (annualized)
Return on average assets									1.31		%				(0.44		%)
Return on average shareholders' equity									10.39		%				(3.35		%)
Return on average tangible shareholders' equity (5)									15.57		%				(4.68		%)
Pre-tax pre-provision income / average assets (6)									1.75		%				1.72		%
Efficiency ratio (FTE) (7)									52.89		%				51.68		%
NM - Not Meaningful

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S&T Bancorp, Inc.
Consolidated Selected Financial Data
Unaudited S&T Earnings Release - 7

			2021						2021						2020
			Second						First						Second
(dollars in thousands)			Quarter						Quarter						Quarter
ASSETS
Cash and due from banks, including interest-bearing deposits			$985,278						$671,429						$351,365
Securities, at fair value			840,375						817,299						804,366
Loans held for sale			7,648						12,794						14,259
Commercial loans:
Commercial real estate			3,246,533						3,284,555						3,345,513
Commercial and industrial			1,774,358						1,931,711						2,140,355
Commercial construction			478,153						460,417						459,264
Total Commercial Loans			5,499,044						5,676,683						5,945,132
Consumer loans:
Residential mortgage			859,329						881,245						971,023
Home equity			547,658						530,350						539,519
Installment and other consumer			88,210						80,646						79,816
Consumer construction			13,110						14,244						13,068
Total Consumer Loans			1,508,307						1,506,485						1,603,426
Total Portfolio Loans			7,007,351						7,183,168						7,548,558
Allowance for credit losses			(109,636)						(115,101)						(114,609)
Total Portfolio Loans, Net			6,897,715						7,068,067						7,433,949
Federal Home Loan Bank and other restricted stock, at cost			10,106						12,199						15,151
Goodwill			373,424						373,424						373,289
Other assets			381,286						373,767						481,917
Total Assets			$9,495,832						$9,328,979						$9,474,296
LIABILITIES
Deposits:
Noninterest-bearing demand			$2,668,833						$2,539,594						$2,250,958
Interest-bearing demand			979,300						976,225						1,055,261
Money market			2,047,254						2,002,857						2,121,588
Savings			1,050,256						1,036,927						916,268
Certificates of deposit			1,269,621						1,320,425						1,523,841
Total Deposits			8,015,264						7,876,028						7,867,916
Borrowings:
Securities sold under repurchase agreements			68,587						67,417						92,159
Short-term borrowings			—						—						84,541
Long-term borrowings			22,969						23,282						49,489
Junior subordinated debt securities			64,113						64,097						64,053
Total Borrowings			155,669						154,796						290,242
Other liabilities			136,166						129,877						180,361
Total Liabilities			8,307,099						8,160,701						8,338,519
SHAREHOLDERS' EQUITY
Total Shareholders' Equity			1,188,733						1,168,278						1,135,777
Total Liabilities and Shareholders' Equity			$9,495,832						$9,328,979						$9,474,296
Capitalization Ratios
Shareholders' equity / assets			12.52		%				12.52		%				11.99		%
Tangible common equity / tangible assets (8)			8.88		%				8.81		%				8.30		%
Tier 1 leverage ratio			9.52		%				9.71		%				8.89		%
Common equity tier 1 capital			11.98		%				11.84		%				10.70		%
Risk-based capital - tier 1			12.40		%				12.26		%				11.10		%
Risk-based capital - total			14.00		%				13.93		%				12.74		%

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S&T Bancorp, Inc.
Consolidated Selected Financial Data
Unaudited S&T Earnings Release - 8

			2021						2021						2020
			Second						First						Second
(dollars in thousands)			Quarter						Quarter						Quarter
Net Interest Margin (FTE) (QTD Averages)
ASSETS
Interest-bearing deposits with banks			$785,465			0.09%			$302,219			0.09%			$163,019			0.08%
Securities, at fair value			826,861			2.19%			782,118			2.34%			785,229			2.56%
Loans held for sale			4,353			3.01%			6,360			2.83%			9,931			3.08%
Commercial real estate			3,251,894			3.69%			3,253,641			3.76%			3,389,616			4.23%
Commercial and industrial			1,890,538			3.90%			1,957,459			4.31%			2,200,148			3.61%
Commercial construction			462,928			3.34%			485,269			3.37%			430,912			3.75%
Total Commercial Loans			5,605,359			3.73%			5,696,369			3.91%			6,020,676			3.97%
Residential mortgage			863,254			4.17%			897,427			4.22%			976,916			4.20%
Home equity			535,933			3.50%			532,708			3.65%			543,770			3.69%
Installment and other consumer			84,259			6.05%			79,907			6.33%			79,944			6.34%
Consumer construction			13,264			6.39%			15,908			4.79%			12,758			4.58%
Total Consumer Loans			1,496,710			4.06%			1,525,950			4.14%			1,613,388			4.14%
Total Portfolio Loans			7,102,069			3.80%			7,222,319			3.96%			7,634,064			4.00%
Total Loans			7,106,422			3.80%			7,228,679			3.96%			7,643,995			4.00%
Federal Home Loan Bank and other restricted stock			10,529			4.51%			11,242			4.94%			19,709			3.75%
Total Interest-earning Assets			8,729,277			3.31%			8,324,259			3.67%			8,611,952			3.80%
Noninterest-earning assets			704,635						756,273						817,767
Total Assets			$9,433,911						$9,080,532						$9,429,719
LIABILITIES AND SHAREHOLDERS' EQUITY
Interest-bearing demand			$998,134			0.09%			$895,891			0.10%			$1,033,905			0.24%
Money market			2,037,976			0.18%			1,968,779			0.19%			2,076,483			0.50%
Savings			1,044,899			0.03%			995,228			0.06%			887,357			0.07%
Certificates of deposit			1,291,194			0.45%			1,344,604			0.65%			1,560,885			1.51%
Total Interest-bearing Deposits			5,372,203			0.20%			5,204,503			0.27%			5,558,630			0.67%
Securities sold under repurchase agreements			67,838			0.10%			64,653			0.15%			85,302			0.25%
Short-term borrowings			0			—%			25,556			0.19%			178,273			0.38%
Long-term borrowings			23,113			2.01%			23,471			2.00%			49,774			2.53%
Junior subordinated debt securities			64,103			3.06%			64,088			3.09%			64,044			3.58%
Total Borrowings			155,054			1.61%			177,768			1.46%			377,393			1.18%
Total Interest-bearing Liabilities			5,527,256			0.24%			5,382,271			0.31%			5,936,023			0.70%
Noninterest-bearing liabilities			2,727,653						2,538,149						2,302,676
Shareholders' equity			1,179,002						1,160,113						1,191,020
Total Liabilities and Shareholders' Equity			$9,433,911						$9,080,532						$9,429,719
Net Interest Margin (9)						3.16%						3.47%						3.31%

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S&T Bancorp, Inc.
Consolidated Selected Financial Data
Unaudited S&T Earnings Release - 9

									Six Months Ended June 30,
(dollars in thousands)									2021						2020
Net Interest Margin (FTE) (YTD Averages)
ASSETS
Interest-bearing deposits with banks									$545,177			0.09%			$131,332			0.59%
Securities, at fair value									804,613			2.26%			786,043			2.55%
Loans held for sale									5,351			2.90%			5,899			3.19%
Commercial real estate									3,252,763			3.72%			3,399,150			4.48%
Commercial and industrial									1,923,813			4.10%			1,975,913			4.02%
Commercial construction									474,037			3.36%			408,638			4.19%
Total Commercial Loans									5,650,613			3.82%			5,783,701			4.30%
Residential mortgage									880,246			4.20%			983,891			4.19%
Home equity									534,329			3.58%			541,981			4.26%
Installment and other consumer									82,095			6.19%			79,812			6.67%
Consumer construction									14,578			5.52%			11,633			4.59%
Total Consumer Loans									1,511,249			4.10%			1,617,317			4.34%
Total Portfolio Loans									7,161,862			3.88%			7,401,018			4.31%
Total Loans									7,167,213			3.88%			7,406,917			4.31%
Federal Home Loan Bank and other restricted stock									10,884			4.73%			21,655			5.47%
Total Interest-earning Assets									8,527,887			3.49%			8,345,947			4.09%
Noninterest-earning assets									730,117						752,576
Total Assets									$9,258,003						$9,098,523
LIABILITIES AND SHAREHOLDERS' EQUITY
Interest-bearing demand									$947,295			0.10%			$987,968			0.41%
Money market									2,003,569			0.18%			2,035,124			0.88%
Savings									1,020,201			0.04%			859,171			0.15%
Certificates of deposit									1,317,751			0.55%			1,581,104			1.66%
Total Interest-bearing deposits									5,288,816			0.23%			5,463,367			0.90%
Securities sold under repurchase agreements									66,254			0.13%			58,046			0.33%
Short-term borrowings									12,707			0.19%			232,319			1.14%
Long-term borrowings									23,291			2.01%			50,809			2.53%
Junior subordinated debt securities									64,095			3.07%			64,120			3.99%
Total Borrowings									166,348			1.53%			405,294			1.65%
Total Interest-bearing Liabilities									5,455,164			0.27%			5,868,661			0.96%
Noninterest-bearing liabilities									2,633,219						2,039,565
Shareholders' equity									1,169,620						1,190,297
Total Liabilities and Shareholders' Equity									$9,258,003						$9,098,523
Net Interest Margin (10)												3.31%						3.42%

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S&T Bancorp, Inc.
Consolidated Selected Financial Data
Unaudited S&T Earnings Release - 10

			2021						2021						2020
			Second						First						Second
(dollars in thousands)			Quarter						Quarter						Quarter
Nonperforming Loans (NPL)
Commercial loans:						% NPL						% NPL						% NPL
Commercial real estate			$82,050			2.53%			$98,606			3.00%			$61,643			1.84%
Commercial and industrial			16,997			0.96%			18,145			0.94%			8,484			0.40%
Commercial construction			384			0.08%			384			0.08%			1,504			0.33%
Commercial Loan Held for Sale			—			—%			2,798			NM			—			—%
Total Nonperforming Commercial Loans			99,431			1.81%			119,933			2.11%			71,631			1.20%
Consumer loans:
Residential mortgage			9,917			1.15%			11,737			1.33%			14,649			1.51%
Home equity			3,150			0.58%			3,441			0.65%			3,814			0.71%
Installment and other consumer			121			0.14%			100			0.12%			19			0.02%
Total Nonperforming Consumer Loans			13,188			0.87%			15,278			1.01%			18,482			1.14%
Total Nonperforming Loans			$112,619			1.61%			$135,211			1.88%			$90,113			1.19%
NM-Not Meaningful

			2021						2021						2020
			Second						First						Second
(dollars in thousands)			Quarter						Quarter						Quarter
Loan Charge-offs (Recoveries)
Charge-offs			$8,737						$6,532						$63,304
Recoveries			(1,264)						(721)						(231)
Net Loan Charge-offs (Recoveries)			$7,473						$5,812						$63,072
Net Loan Charge-offs (Recoveries)
Commercial loans:
Customer fraud			$—						$—						$58,671
Commercial real estate			6,595						698						5,588
Commercial and industrial			795						4,913						3,060
Commercial construction			(2)						(1)						(19)
Total Commercial Loan Charge-offs (Recoveries)			7,388						5,610						67,300
Consumer loans:
Residential mortgage			(57)						71						74
Home equity			10						232						16
Installment and other consumer			132						(102)						682
Total Consumer Loan Charge-offs (Recoveries)			85						202						772
Total Net Loan Charge-offs (Recoveries)			$7,473						$5,812						$68,072

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S&T Bancorp, Inc.
Consolidated Selected Financial Data
Unaudited S&T Earnings Release - 11

									Six Months Ended June 30,
(dollars in thousands)									2021						2020
Loan Charge-offs (Recoveries)
Charge-offs									$15,270						$79,749
Recoveries									(1,985)						(520)
Net Loan Charge-offs (Recoveries)									$13,285						$79,229
Net Loan Charge-offs (Recoveries)
Commercial loans:
Customer fraud									$—						$58,671
Commercial real estate									7,293						6,016
Commercial and industrial									5,708						13,325
Commercial construction									(3)						(21)
Total Commercial Loan Charge-offs/(Recoveries)									12,998						77,991
Consumer loans:
Residential mortgage									15						93
Home equity									242						97
Installment and other consumer									30						1,048
Total Consumer Loan Charge-offs (Recoveries)									287						1,238
Total Net Loan Charge-offs (Recoveries)									$13,285						$79,229

			2021						2021						2020
			Second						First						Second
(dollars in thousands)			Quarter						Quarter						Quarter
Asset Quality Data
Nonperforming loans			$112,619						$135,211						$90,113
OREO			1,145						1,620						2,740
Nonperforming assets			113,764						136,831						92,853
Troubled debt restructurings (nonaccruing)			20,650						29,983						31,755
Troubled debt restructurings (accruing)			14,321						17,916						15,536
Total troubled debt restructurings			34,971						47,899						47,291
Nonperforming loans / total loans			1.61		%				1.88		%				1.19		%
Nonperforming assets / total loans plus OREO			1.62		%				1.90		%				1.23		%
Allowance for credit losses / total portfolio loans			1.56		%				1.60		%				1.52		%
Allowance for credit losses / total portfolio loans excluding PPP			1.64		%				1.72		%				NA
Allowance for credit losses / nonperforming loans			97		%				85		%				127		%
Net loan charge-offs (recoveries)			$7,473						$5,812						$68,072
Net loan charge-offs (recoveries)(annualized) / average loans			0.43		%				0.33		%				3.58		%
NA = Not Applicable

									Six Months Ended June 30,
(dollars in thousands)									2021						2020
Asset Quality Data
Net loan charge-offs (recoveries)									$13,285						$79,229
Net loan charge-offs (recoveries)(annualized) / average loans									0.37		%				2.15		%

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S&T Bancorp, Inc.
Consolidated Selected Financial Data
Unaudited S&T Earnings Release - 12

Definitions and Reconciliation of GAAP to Non-GAAP Financial Measures:

			2021						2021						2020
			Second						First						Second
(dollars in thousands)			Quarter						Quarter						Quarter
(1) Tangible Book Value (non-GAAP)
Total shareholders' equity			$1,188,733						$1,168,278						$1,135,777
Less: goodwill and other intangible assets, net of deferred tax liability			(379,563)						(379,911)						(380,986)
Tangible common equity (non-GAAP)			$809,170						$788,367						$754,791
Common shares outstanding			39,346						39,268						39,263
Tangible book value (non-GAAP)			$20.57						$20.08						$19.22
(2) Return on Average Tangible Shareholders' Equity (non-GAAP)
Net income (loss) (annualized)			$113,778						$129,378						($133,016)
Plus: amortization of intangibles (annualized), net of tax			1,395						1,464						2,072
Net income before amortization of intangibles (annualized)			$115,173						$130,842						($130,944)
Average total shareholders' equity			$1,179,002						$1,160,113						$1,191,020
Less: average goodwill and other intangible assets, net of deferred tax liability			(379,784)						(380,144)						(382,081)
Average tangible equity (non-GAAP)			$799,218						$779,969						$808,939
Return on average tangible shareholders' equity (non-GAAP)			14.41		%				16.78		%				(16.19		%)
(3) PTPP / Average Assets (non-GAAP)
Income (loss) before taxes			$35,338						$39,178						($44,865)
Plus: Provision for credit losses			2,561						3,137						86,759
Total			37,899						42,315						41,894
Total (annualized) (non-GAAP)			$152,012						$171,611						$168,497
Average assets			$9,433,911						$9,080,532						$9,429,719
PTPP / Average Assets (non-GAAP)			1.61		%				1.89		%				1.79		%
(4) Efficiency Ratio (non-GAAP)
Noninterest expense			$45,829						$45,580						$43,478
Net interest income per consolidated statements of net income			$68,304						$70,659						$70,148
Plus: taxable equivalent adjustment			585						664						847
Net interest income (FTE) (non-GAAP)			68,889						71,323						70,995
Noninterest income			15,424						17,236						15,224
Less: net (gains) losses on sale of securities			(29)						—						(142)
Net interest income (FTE) (non-GAAP) plus noninterest income			$84,284						$88,560						$86,077
Efficiency ratio (non-GAAP)			54.37		%				51.47		%				50.51		%

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S&T Bancorp, Inc.
Consolidated Selected Financial Data
Unaudited S&T Earnings Release - 13

									Six Months Ended June 30,
(dollars in thousands)									2021						2020
(5) Return on Average Tangible Shareholders' Equity (non-GAAP)
Net income (loss) (annualized)									$121,535						($39,900)
Plus: amortization of intangibles (annualized), net of tax									1,429						2,040
Net income before amortization of intangibles (annualized)									$122,964						($37,860)
Average total shareholders' equity									$1,169,620						$1,190,297
Less: average goodwill and other intangible assets, net of deferred tax liability									(379,963)						(380,935)
Average tangible equity (non-GAAP)									$789,657						$809,362
Return on average tangible shareholders' equity (non-GAAP)									15.57		%				(4.68		%)
(6) PTPP / Average Assets (non-GAAP)
Income (loss) before taxes									$74,515						($28,867)
Plus: Provision for credit losses									5,699						106,809
Total									80,214						77,942
Total (annualized) (non-GAAP)									$161,758						$156,741
Average assets									$9,258,003						$9,098,523
PTPP / Average Assets (non-GAAP)									1.75		%				1.72		%
(7) Efficiency Ratio (non-GAAP)
Noninterest expense									$91,409						$89,869
Less: merger related expenses									—						(2,342)
Noninterest expense excluding nonrecurring items									$91,409						$87,527
Net interest income per consolidated statements of net income									$138,962						$140,184
Plus: taxable equivalent adjustment									1,249						1,697
Net interest income (FTE) (non-GAAP)									140,211						141,881
Noninterest income									32,661						27,627
Less: net (gains) losses on sale of securities									(29)						(142)
Net interest income (FTE) (non-GAAP) plus noninterest income									$172,843						$169,366
Efficiency ratio (non-GAAP)									52.89		%				51.68		%
(10) Net Interest Margin Rate (FTE) (non-GAAP)
Interest income and dividend income									$146,358						$168,069
Less: interest expense									(7,396)						(27,885)
Net interest income per consolidated statements of net income									138,962						140,184
Plus: taxable equivalent adjustment									1,249						1,697
Net interest income (FTE) (non-GAAP)									$140,211						$141,881
Net interest income (FTE) (annualized)									$282,746						$285,321
Average interest-earning assets									$8,527,886						$8,345,947
Net interest margin - (FTE) (non-GAAP)									3.31		%				3.42		%

- more -

S&T Bancorp, Inc.
Consolidated Selected Financial Data
Unaudited S&T Earnings Release - 14

Definitions and Reconciliation of GAAP to Non-GAAP Financial Measures:

			2021						2021						2020
			Second						First						Second
(dollars in thousands)			Quarter						Quarter						Quarter
(8) Tangible Common Equity / Tangible Assets (non-GAAP)
Total shareholders' equity			$1,188,733						$1,168,278						$1,135,777
Less: goodwill and other intangible assets, net of deferred tax liability			(379,563)						(379,911)						(380,986)
Tangible common equity (non-GAAP)			$809,170						$788,367						$754,791
Total assets			$9,495,832						$9,328,979						$9,474,296
Less: goodwill and other intangible assets, net of deferred tax liability			(379,563)						(379,911)						(380,986)
Tangible assets (non-GAAP)			$9,116,268						$8,949,068						$9,093,310
Tangible common equity to tangible assets (non-GAAP)			8.88		%				8.81		%				8.30		%
(9) Net Interest Margin Rate (FTE) (non-GAAP)
Interest income and dividend income			$71,577						$74,781						$80,479
Less: interest expense			(3,273)						(4,122)						(10,331)
Net interest income per consolidated statements of net income			68,304						70,659						70,148
Plus: taxable equivalent adjustment			585						664						847
Net interest income (FTE) (non-GAAP)			$68,889						$71,323						$70,995
Net interest income (FTE) (annualized)			$276,313						$289,253						$285,540
Average interest- earning assets			$8,729,277						$8,324,259						$8,611,952
Net interest margin (FTE) (non-GAAP)			3.16		%				3.47		%				3.31		%

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