14. Equity and Stock-Based Compensation

Stock Repurchase Plans

All repurchased shares have been retired.

Stock-Based Compensation Expense

Stock-based compensation expenses of $0.5 million, $0.4 million and $0.3 million for 2022, 2021 and 2020, respectively, are included in selling, general and administrative expenses. As of September 30, 2022, total compensation cost related to non-vested stock options not yet recognized is $0.7 million, which is expected to be recognized over the next 1.19 years on a weighted-average basis.

Amtech Equity Compensation Plans

The 2022 Plan, under which 1,000,000 shares could be granted, was adopted by the Board of Directors in November 2021, and approved by the shareholders in March 2022.

The 2007 Plan, under which 500,000 shares could be granted, was adopted by the Board in April 2007, and approved by the shareholders in May 2007. The 2007 Plan was amended in 2009, 2014 and 2015 to add 2,500,000 shares. The

plan was also amended in 2019 to extend the term of the plan and allow for the grant of restricted stock units. Upon the adoption of the 2022 Plan, no further awards will be granted from the 2007 Plan. Previously issued awards will remain outstanding in accordance with their terms.

The Non-Employee Directors Stock Option Plan was approved by the shareholders in 1996 for issuance of up to 100,000 shares of common stock to directors. The Non-Employee Directors Stock Option Plan was amended in 2005, 2009 and 2014 to add 400,000 shares. The plan was also amended in 2020 to extend the term of the plan. Upon the adoption of the 2022 Plan as stated above, no further awards will be granted from the Non-Employee Directors Stock Option Plan. Previously issued awards will remain outstanding in accordance with their terms.

Stock Options

Stock options issued under the terms of our equity compensation plans have, or will have, an exercise price equal to or greater than the fair market value of the common stock at the date of the option grant and expire no later than 10 years from the date of grant. Options issued under the plans vest over 1 to 3 years. We estimated the fair value of stock option awards on the date of grant using the Black-Scholes option pricing model using the following assumptions:

The aggregate intrinsic values of options outstanding and options exercisable as of September 30, 2022 were approximately $1.0 million and $0.7 million, respectively, which represents the total pre-tax intrinsic value, based on our closing stock price of $8.50 per share as of September 30, 2022, the last business day of our fiscal year, which would have been received by the option holders had all option holders exercised their options as of that date. The total intrinsic value of stock options exercised during the fiscal years ended September 30, 2022, 2021 and 2020 was $0.8 million, $0.8 million and $0.1 million, respectively.