Profile: Key Statistics: (Data as of 03.31.19) S&T Bancorp, Inc. is a $7.2 billion financial holding company headquartered in Indiana, PA, located Stock Price $39.53 Total Assets (in $ millions) $7,229 about 55 miles northeast of Pittsburgh, PA. Market Cap (in $ billions) $1.4 Common BV/Share $27.47 Founded in 1902 with a single location in Dividend Yield (annualized) 2.73% Indiana, PA, S&T Bancorp, Inc. has Tangible BV/Share (non-GAAP) $19.04 Price/Earnings (LTM) 13.1 expanded to five markets including Western PA, Central PA, Northeast OH, Central OH and Upstate NY. S&T provides a full range of financial services to individuals and businesses in PA, Northeast OH and Central OH and has a loan production office in Upstate NY. Investment Thesis: S&T Operates in • Above peer performance Five Markets • Demonstrated expense discipline and efficiency • Organic growth • Strategic and effective mergers and expansion • Stable markets with     long term oil and gas benefit • Sound asset quality • The right size Recent Mergers and Expansions: April 22, 2019 November 1, 2016 Northeast OH Northeast OH Branch opens in Cuyahoga Falls, OH branch relocates to expanded facility April 4, 2019 March 23, 2015 Central Ohio Market Upstate NY Branch opens in Hillard, OH LPO office opens to service Rochester, November 16, 2016 NY Western PA LPO opens in Pittsburgh, PA March 4, 2015 Central PA Integrity Bank acquired

Senior Management: Financial Highlights: Todd D. Brice Chief Executive Officer 2017 Excludes David G. Antolik 1Q19 2018 2017 DTA(2) 2016 President and Chief Lending Officer Net Income (in thousands) $22,928 $105,334 $72,968 $86,401 $71,392 Mark Kochvar Diluted Earnings per Share $0.66 $3.01 $2.09 $2.47 $2.05 Chief Financial Officer Dividends Declared per Share $0.27 $0.99 $0.82 $0.77 David P. Ruddock Chief Operating Officer Total Assets (in millions) $7,229 $7,252 $7,060 $6,943 Rebecca A. Stapleton Chief Banking Officer Total Loans (in millions) $5,938 $5,949 $5,766 $5,615 Investor Relations Contact: Total Deposits (in millions) $5,833 $5,674 $5,428 $5,272 Mark Kochvar S&T Bancorp, Inc. Return on Average Assets(1) 1.29% 1.50% 1.03% 1.22% 1.08% 800 Philadelphia Street (1) Indiana, PA 15701 Return on Average Equity 9.84% 11.60% 8.37% 9.90% 8.67% 724.465.4826 Return on Tangible Equity(1)(non-GAAP) 14.27% 17.14% 12.77% 15.08% 13.71% mark.kochvar@stbank.com Net Interest Margin (FTE) (non-GAAP) 3.71% 3.64% 3.56% 3.47% For more information visit stbancorp.com or stbank.com. Nonperforming Assets/ Loans + OREO 0.85% 0.83% 0.42% 0.77% Common stock traded on the NASDAQ under the symbol STBA Allowance for Loan Losses/ Total Loans 1.03% 1.03% 0.98% 0.94% Analyst Coverage: Net Loan Charge-offs/Average Loans(1) 0.36% 0.18% 0.18% 0.25% The following analysts published research about S&T Bancorp, Inc. in 2019. Risk-based Capital - Total 13.19% 13.21% 12.55% 11.86% Boenning & Scattergood Tangible Common Equity/ Tangible Matthew Schultheis • 610.832.5290 Assets (non-GAAP) 9.42% 9.28% 8.72% 8.23% mschultheis@boenninginc.com (1) Quarterly metrics on an annualized basis DA Davidson Russell Gunther • 212.223.5403 rgunther@dadco.com Total Annualized Shareholder Return Keefe, Bruyette & Woods Includes reinvested dividends Collyn Gilbert • 973.549.4092 (Data as of 03.31.19) collyn.gilbert@kbw.com Piper Jaffray 1 YR 3 YR 5 YR 10 YR Matthew Breese • 617.654.0728 matthew.m.breese@pjc.com STBA 1.46 % 18.25% 13.62% 9.42% Raymond James S&P 600 Bank (5.83)% 13.24% 9.00% 12.76% Daniel Cardenas • 312.655.2986 daniel.cardenas@raymondjames.com NASDAQ Bank (11.03)% 12.07% 7.96% 11.22% S&P 500 9.48 % 13.52% 10.90% 15.91% Source: Bloomberg (2)These are non-GAAP numbers that adjust for the effects of a one-time, non-cash re-measurement of $13.4 million of our deferred tax asset in 2017. This document may contain “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Such statements involve risks and uncertainties that could cause actual results to differ materially from the results discussed in these statements. These risks are detailed in the company’s latest form 10- K filed with the Securities and Exchange Commission and any subsequently filed reports containing updates to these risks. Any such forward-looking statement or other information herein speaks only as of the particular dates referenced or the date such information or statement is made, and S&T undertakes no obligation to update any such information. This document also contains or references, certain non-GAAP financial measures. Although S&T believes that these measures enhance investors’ understanding of S&T’s business and performance, these non-GAAP financial measures should not be considered an alternative to GAAP, and should be read in conjunction with the audited financial statements and analysis as presented in the Annual Report on Form 10-K as well as the unaudited financial statements and analyses as presented in the respective Quarterly Reports on Forms 10-Q for S&T Bancorp, Inc. and subsidiaries.