Exhibit 99.1

S&T Bancorp Inc. STBA NASDAQ LISTED

Exhibit 99.1

Profile:

S&T Bancorp, Inc. is a $6.2 billion financial holding company headquartered in Indiana, PA, located about 55 miles northeast of Pittsburgh, PA. Founded in 1902 with a single location in Indiana, PA, S&T Bancorp, Inc. has grown to 63 branch offices that provide a full range of financial services to individuals and businesses in 16 southwestern and southcentral Pennsylvania counties. Additionally, S&T has loan production offices in northeast and central Ohio, and western New York.

Investment Thesis:

Above peer performance

Strategic and effective mergers and expansion

Demonstrated expense discipline and efficiency

Organic growth

Excellent asset quality

Stable regional economy with long term oil and gas benefit

Recent Mergers and Expansions: March 23, 2015

S&T Bank loan production office opens to service western New York. March 4, 2015

S&T Bancorp merges with Integrity Bancshares in southcentral PA, adding 8 offices in 4 counties, $789 million in loans, and $722 million in deposits.

June 18, 2014

S&T Bank branch opens in State College, PA.

January 21, 2014

S&T Bank loan production office opens to service central Ohio.

Key Statistics:

(Data as of 09.30.15)

Total Assets (in $ millions) $6,215

Common BV/Share $22.63

Tangible BV/Share $14.12

Stock Price $32.62

Market Cap (in $ billions) $1.14

Dividend Yield (annualized) 2.21%

Price/Earnings (LTM) 16.6

63 Branches in 16 Pennsylvania Counties &

3 Loan Production Offices in Ohio and New York

Rochester

Akron

State College

Pittsburgh

Harrisburg

Columbus

Dauphin

Cumberland

Lancaster

York

S&T Bank

Loan Production Offices

Total Annualized Shareholder Return

Includes reinvested dividends

(Data as of 09.30.15)

1 YR 3 YR 5 YR 10 YR

STBA 42.63% 26.23% 16.72% 1.78%

NASDAQ Bank 13.95% 16.05% 13.29% 1.49%

KRX-Dow Jones KBW Regional Bank 14.47% 15.27% 14.24% 1.12%

S&P 500 -0.62% 12.36% 13.31% 6.79%

Source: Bloomberg

MEMBER FDIC

EQUAL HOUSING LENDER

S&T Bancorp Inc. STBA NASDAQ LISTED

Senior Management:

Todd D. Brice

President and Chief Executive Officer

Mark Kochvar

Senior Executive Vice President, Chief Financial Officer

David G. Antolik

Senior Executive Vice President, Chief Lending Officer

David P. Ruddock

Senior Executive Vice President, Chief Operating Officer

Rebecca A. Stapleton

Senior Executive Vice President, Chief Banking Officer

Investor Relations Contact:

Mark Kochvar

S&T Bancorp, Inc.

800 Philadelphia Street Indiana, PA 15701 724.465.4826 mark.kochvar@stbank.net For more information visit stbancorp.com or stbank.com.

Common stock traded on the NASDAQ under the symbol STBA

Analyst Coverage:

The following analysts published research about S&T Bancorp, Inc. in 2015.

Boenning & Scattergood Matthew Schultheis • 610.832.5290 mschultheis@boenninginc.com Keefe, Bruyette & Woods Collyn Gilbert

973.549.4092 collyn.gilbert@kbw.com Piper Jaffray Matthew Breese

207.233.4399 matthew.m.breese@pjc.com Raymond James William Wallace

301.657.1548 william.wallace@raymondjames.com

Financial Highlights:

2015 2015 2015 2014 2013

Q3 Q2 Q1 Full Year Full Year

Net Income (in $ thousands) $18,635 $18,188 $12,835 $57,910 $50,539

Diluted Earnings per Share $0.54 $0.52 $0.41 $1.95 $1.70

Dividends Declared per Share $0.18 $0.18 $0.18 $0.68 $0.61

Total Assets (in $ millions) $6,215 $6,134 $5,971 $4,965 $4,533

Total Loans (in $ millions) $4,940 $4,812 $4,690 $3,872 $3,568

Total Deposits (in $ millions) $4,877 $4,859 $4,829 $3,909 $3,672

Return on Average Assets (annualized) 1.20% 1.21% 0.99% 1.22% 1.12%

Return on Average Equity (annualized) 9.51% 9.52% 7.85% 9.71% 9.21%

Return on Tangible Equity (annualized) 15.61% 15.79% 11.80% 14.02% 13.94 %

Net Interest Margin (FTE) (annualized) 3.61% 3.67% 3.48% 3.50% 3.50%

Nonperforming Assets/Loans + OREO 0.49% 0.41% 0.41% 0.33% 0.64%

Allowance for Loan Losses/Total Loans 1.01% 1.02% 1.03% 1.24% 1.30%

Net Loan Charge-offs (annualized) /

Average Loans 0.17% 0.11% 0.10% 0.00% 0.25%

Risk-based Capital - Total 11.58% 11.48% 11.86% 14.27% 14.36%

Tangible Common Equity/Tangible Assets 8.30% 8.14% 8.22% 9.00% 9.03%

Our Reputation Speaks for Itself

Named to the prestigous Sandler O’Neill Sm-All Stars Class of 2013, 2014, and 2015.

Superior Customer Service

Consistently ranked high in customer satisfaction.

American Heart Association

S&T recognized as a Gold Level Fit-Friendly Worksite in 2014.

S&T Bank

One customer at a time.

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-Q and 10-K filed with the Securities and Exchange Commission.

This document also contains or references, certain non-GAAP financial measures, such as net interest margin (FTE). 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.