FOR IMMEDIATE RELEASE

S & T Bancorp, Inc. Announces Fourth Quarter and Full Year 2018 Results

- Record Full Year Net Income of $105.3 Million-

Indiana, Pa. - January 31, 2019 - S & T Bancorp, Inc. (S & T) (NASDAQ: STBA), the holding company for S & T Bank, with operations in five markets including Western Pennsylvania, Central Pennsylvania, Northeast Ohio, Central Ohio, and Upstate New York, announced its fourth quarter and full year 2018 earnings. Net income was $26.9 million, or $0.77 per diluted share, for the fourth quarter compared to net income of $9.3 million, or $0.27 per diluted share for the fourth quarter of 2017, and $30.9 million, or $0.88 per diluted share for the third quarter of 2018. The third quarter of 2018 results were positively impacted by a one-time reduction to tax expense of $2.9 million, or $0.08 per diluted share, related to a tax deduction for a pension contribution at a 35% corporate tax rate versus the current rate of 21%.

Net income was a record $105.3 million, or $3.01 per diluted share, for the year ended December 31, 2018 compared to net income of $73.0 million, or $2.09 per diluted share, for 2017. As a result of the December 2017 enactment of the Tax Cuts and Jobs Act, additional tax expense of $13.4 million was recognized to re-measure the net deferred tax asset (DTA) in the fourth quarter of 2017. Excluding the net DTA re-measurement, fourth quarter of 2017 net income was $22.7 million (non-GAAP) and diluted earnings per share was $0.65 (non-GAAP) and full year 2017 net income was $86.4 million (non-GAAP) and diluted earnings per share was $2.47 (non-GAAP).

Fourth Quarter of 2018 Highlights:

Full Year 2018 Highlights:

“We are pleased to announce another successful year with record net income for 2018,” said Todd Brice, chief executive officer of S & T. “We have excellent momentum as we move into 2019 thanks to our great team of bankers and our robust markets.”

Fourth Quarter of 2018 Results

Net Interest Income

Net interest income increased $0.6 million to $59.9 million compared to $59.3 million in the third quarter of 2018. The increase in net interest income is due to higher average loans of $112.1 million. Net interest margin on a fully taxable equivalent basis (FTE) (non-GAAP) declined 2 basis points to 3.65% compared to 3.67% in the prior quarter. The decrease in the net interest margin rate is due to an increasingly competitive deposit environment combined with stronger growth in the fourth quarter.

Asset Quality

Asset quality trends were impacted by three commercial nonaccrual loans totaling $23.6 million in the fourth quarter of 2018. These nonaccrual loans resulted in loan charge-offs of $2.4 million and specific reserves of $1.5 million for the fourth quarter of 2018. Total nonperforming loans increased $25.3 million to $46.1 million, or 0.77% of total loans, at December 31, 2018 compared to $20.7 million, or 0.36% of total loans, at September 30, 2018. Net charge-offs were $2.3 million, or 0.15% of average loans on an annualized basis, in the fourth quarter of 2018 compared to net charge-offs of $0.4 million, or 0.03% of average loans on an annualized basis, in the third quarter of 2018. The provision for loan losses was $2.7 million in the fourth quarter of 2018 compared to $0.5 million in the third quarter of 2018. The allowance for loan losses was $61.0 million, or 1.03% of total portfolio loans, at December 31, 2018 compared to $60.6 million, or 1.04% of total portfolio loans, at September 30, 2018.

Noninterest Income and Expense

Noninterest income decreased $0.9 million to $11.1 million in the fourth quarter of 2018 compared to $12.0 million in the third quarter of 2018. Noninterest expense decreased $0.7 million to $36.4 million in the fourth quarter of 2018 compared to $37.1 million in the third quarter of 2018. Both noninterest income and noninterest expense were impacted by a $0.8 million mark-to-market adjustment for a deferred compensation plan due to the negative performance in the stock market in the fourth quarter.  The mark-to-market adjustment of $0.8 million is recorded in other noninterest income and offset in salaries and employee benefits resulting in no impact to net income.

Additionally, other noninterest income was impacted by a negative mark-to-market adjustment of $0.5 million for equity securities offset by higher commercial loan swap fees of $0.8 million compared to the third quarter of 2018.

Expenses were well controlled for the fourth quarter with an efficiency ratio of 50.64% compared to 51.33% in the third quarter of 2018.

Financial Condition

Total assets grew $146.9 million to $7.3 billion at December 31, 2018 compared to $7.1 billion at September 30, 2018. Total portfolio loans increased $138.8 million, or 9.5% annualized, compared to September 30, 2018. Commercial loan growth was strong with an increase in commercial real estate loans of $95.5 million, or 13.4% annualized, and an increase in commercial and industrial loans of $42.0 million, or 11.5% annualized, compared to September 30, 2018. Consumer loans increased $27.9 million with growth mainly in residential mortgages of $26.8 million, or 15.2% annualized, compared to September 30, 2018. Total deposit growth was strong during the quarter with deposits increasing $206.4 million, or 15.0% annualized. Deposit growth was mainly in money market of $114.9 million, or 33.3% annualized, and certificates of deposit of $102.6 million, or 31.1% annualized.

On March 19, 2018, S & T's Board of Directors authorized a $50.0 million share repurchase plan. During the fourth quarter of 2018, there were 321,731 common shares repurchased for a cost of $12.3 million, or at an average price of $38.10 per common share. Up to an additional $37.7 million of common shares may be repurchased under this authorization through August 31, 2019.

S & T’s risk-based capital ratios were relatively unchanged compared to the third quarter of 2018 due to strong loan growth and share repurchases. All capital ratios remain significantly above the well-capitalized thresholds of federal bank regulatory agencies.

Full Year 2018 Results

Full year net income was a record $105.3 million, or $3.01 per diluted share, for the year ended December 31, 2018 compared to net income of $73.0 million, or $2.09 per diluted share, for 2017. Excluding the net DTA re-measurement of $13.4 million, full year 2017 net income was $86.4 million (non-GAAP) and diluted earnings per share was $2.47 (non-GAAP). Net income in 2018 was positively impacted by the Tax Cuts and Jobs Act which lowered the federal corporate tax rate from 35% to 21% effective January 1, 2018. Net interest income increased $8.7 million, or 3.9%, and net interest margin (FTE) (non-GAAP) increased 8 basis points to 3.64% compared to 3.56% for 2017 due to higher short-term rates. Noninterest income decreased $6.3 million mainly due to the sale of our insurance business on January 1, 2018. Expenses were well controlled during 2018 with an efficiency ratio (non-GAAP) of 50.60% compared to 51.77% for 2017. To view an infographic featuring 2018 highlights, click here. [Refer to Exhibit 99.2 ]

Dividend

The Board of Directors of S & T declared a $0.27 per share cash dividend at its regular meeting held January 28, 2019. This is an increase of 22.7% compared to a common stock dividend of $0.22 per share declared in the same period in the prior year. The dividend is payable February 28, 2019 to shareholders of record on February 14, 2019. Dividends declared in 2018 increased $0.17, or 20.7%, to $0.99 compared to $0.82 for 2017.

Non-GAAP Financial Measures

This release presents certain non-GAAP financial measures. For a reconciliation to the most directly comparable GAAP measures, see "Definitions and Reconciliation of GAAP to Non-GAAP Financial Measures" in the accompanying tables.

Conference Call

S & T will host its fourth quarter 2018 earnings conference call live over the Internet at 1:00 p.m. ET on Thursday, January 31, 2019. To access the webcast, go to S & T’s webpage at www.stbancorp.com and click on “Events & Presentations.” Select "4th Quarter 2018 Conference Call” and follow the instructions.

About S & T Bancorp, Inc.

S & T Bancorp, Inc. is a $7.3 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, a full-service financial institution, was established in 1902, and operates in five markets including Western Pennsylvania, Central Pennsylvania, Northeast Ohio, Central Ohio, and Upstate New York. For more information visit http://www.stbancorp.com/, http://www.stbank.com/, and follow us on Facebook, Instagram, and Linkedin.

This information contains certain 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

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