Table of Contents Stock-based compensation expense relating to the EIP, SDP and RSAP totaled $3.29 million in 2020, $2.76 million in 2019, and $3.55 million in 2018. The total income tax benefit recognized in the accompanying Consolidated Statements of Income related to stock-based compensation was $0.77 million in 2020, $0.65 million in 2019, and $0.86 million in 2018. Unrecognized stock-based compensation expense related to non-vested stock awards (EIP/SDP/RSAP) was $7.63 million at December 31, 2020. At such date, the weighted-average period over which this unrecognized expense was expected to be recognized was 3.44 years. The fair value of non-vested stock awards for the purposes of recognizing stock-based compensation expense is market price of the stock on the measurement date, which, for the Company’s purposes is the date of the award. Employee Stock Purchase Plan  — The Company offers an ESPP for substantially all employees with at least two years of service on the effective date of an offering under the plan. Eligible employees may elect to purchase any dollar amount of stock, so long as such amount does not exceed 25% of their base rate of pay and the aggregate stock accrual rate for all offerings does not exceed $25,000 in any calendar year. The purchase price for shares offered is the lower of the closing market bid price for the offering date or the average market bid price for the five business days preceding the offering date. The purchase price and premium/(discount) to the actual market closing price on the offering date for the 2020, 2019, and 2018 offerings were $34.35 (1.78%), $43.81 (0.14%), and $53.84 (-0.09%), respectively. Payment for the stock is made through payroll deductions over the offering period, and employees may discontinue the deductions at any time and exercise the option or take the funds out of the program. The most recent offering began June 1, 2020 and runs through June 1, 2022, with $304,635 in stock value to be purchased at $34.35 per share. The following table shows the composition of income tax expense. The following table shows the reasons for the difference between income tax expense and the amount computed by applying the statutory federal income tax rate (21%) to income before income taxes. The tax expense related to gains (losses) on investment securities available-for-sale for the years 2020, 2019, and 2018 was approximately $67,000, $0, and $(83,000), respectively. Note 17 — Income Taxes Year Ended December 31  (Dollars in thousands)  2020 2019 2018 Current: Federal $ 42,411 $ 28,130  $ 20,167  State 6,629 5,739  2,996  Total current 49,040 33,869  23,163  Deferred: Federal (21,865) (5,135) (875) State (2,295) (595) 1,200  Deferred tax liability remeasurement — —  (875) Total deferred (24,160) (5,730) (550) Total provision $ 24,880 $ 28,139  $ 22,613  2020 2019 2018 Year Ended December 31  (Dollars in thousands) Amount Percent of Pretax Income Amount Percent of Pretax Income Amount Percent of Pretax Income Statutory federal income tax $ 22,332 21.0 % $ 25,232  21.0  % $ 22,056  21.0  % (Decrease) increase in income taxes resulting from: Tax-exempt interest income (439) (0.4) (552) (0.5) (650) (0.6) State taxes, net of federal income tax benefit 3,424 3.2 4,064  3.4  3,315  3.2  Deferred tax liability remeasurement — — —  —  (875) (0.8) Other (437) (0.4) (605) (0.5) (1,233) (1.3) Total $ 24,880 23.4 % $ 28,139  23.4  % $ 22,613  21.5  % 74