On May 5, 2021, the Company’s stockholders approved the Great Lakes Dredge & Dock Corporation 2021 Long-Term Incentive Plan (the “Incentive Plan”), which previously had been approved by the Company’s board of directors subject to stockholder approval. The Incentive Plan replaces the 2017 Long-Term Incentive Plan (the “Prior Plan”) and is largely based on the Prior Plan, but with updates to the available shares and other administrative changes. The Incentive Plan permits the granting of stock options, stock appreciation rights, restricted stock and restricted stock units to the Company’s employees and directors for up to 1.5 million shares of common stock, plus the number of shares that remained available for future grant under the Prior Plan as of the effectiveness of the Incentive Plan.

The Prior Plan permitted the granting of stock options, stock appreciation rights, restricted stock and restricted stock units to its employees and directors for up to 3.3 million shares of common stock, plus an additional 1.7 million shares underlying equity awards issued under the 2007 Long-Term Incentive Plan. The Company may also issue share-based compensation as inducement awards to new employees upon approval of the Board of Directors.

Compensation cost charged to expense related to share-based compensation arrangements was $4,288, $5,188 and $6,754, for the years ended December 31, 2022, 2021 and 2020, respectively.

The NQSO awards were granted with an exercise price equal to the market price of the Company’s common stock at the date of grant. The option awards generally vest in three equal annual installments commencing on the first anniversary of the grant date, and have ten year exercise periods.

The fair value of the NQSOs was determined at the grant date using a Black-Scholes option pricing model, which requires the Company to make several assumptions. The risk-free interest rate is based on the U.S. Treasury yield curve in effect for the expected term of the option at the time of grant. The annual dividend yield on the Company’s common stock is based on estimates of future dividends during the expected term of the NQSOs. The expected life of the NQSOs was determined from historical exercise data providing a reasonable basis upon which to estimate the expected life. The volatility assumptions were based on historical volatility of Great Lakes. There is not an active market for options on the Company’s common stock and, as such, implied volatility for the Company’s stock was not considered. Additionally, the Company’s general policy is to issue new shares of registered common stock to satisfy stock option exercises or grants of restricted stock. No NQSO awards were granted in 2022, 2021 and 2020. The aggregate intrinsic value of stock options represents the difference between market value on the date of exercise and the option price. The aggregate intrinsic value of stock options exercised during 2022, 2021 and 2020 was $212, $1,351 and $779, respectively.

A summary of stock option activity under the Incentive Plan as of December 31, 2022, and changes during the year ended December 31, 2022, is presented below:


Options	Shares			Weighted Average Exercise Price		Weighted-Average Remaining Contract Term (yrs)		Aggregate Intrinsic Value ($000's)
Outstanding as of January 1, 2022		105		$	7.50
Granted		—			—
Exercised		(29	)		7.19
Forfeited or Expired		—			—
Outstanding as of December 31, 2022		76		$	7.61		1.2	$	—

Vested at December 31, 2022		76		$	7.61		1.2	$	—

RSUs primarily vest in equal portions over the three year vesting period. The fair value of RSUs was based upon the Company’s stock price on the date of grant. A summary of the status of the Company’s non-vested RSUs as of December 31, 2022, and changes during the year ended December 31, 2022, is presented below:


Non-vested Restricted Stock Units	Shares			Weighted-Average Grant-Date Fair Value
Outstanding as of January 1, 2022		1,044		$	10.57
Granted		487			13.85
Vested		(393	)		9.86
Forfeited		(31	)		11.15
Outstanding as of December 31, 2022		1,107		$	12.62

Expected to vest at December 31, 2022		997		$	12.67

As of December 31, 2022, there was $7,844 of total unrecognized compensation cost related to non-vested RSUs granted under the Incentive Plan. That cost for non-vested RSUs is expected to be recognized over a weighted-average period of 1.9 years.

The Incentive Plan permits the employee to use vested shares from RSUs to satisfy the grantee’s U.S. federal income tax liability resulting from the issuance of the shares through the Company’s retention of that number of common shares having a market value as of the vesting date equal to such tax obligation up to the minimum statutory withholding requirements. The amount related to shares used for such tax withholding obligations was approximately $2,185 and $4,250 for the years ended December 31, 2022 and 2021, respectively.

The Company uses a combination of cash and share-based compensation to attract and retain qualified candidates to serve on its Board of Directors. Compensation is paid to non-employee directors. Directors who are employees receive no additional compensation for services as members of the Board or any of its committees. Share-based compensation is paid pursuant to the Incentive Plan. Each non-employee director of the Company receives an annual retainer of $155, payable quarterly in arrears, and is generally paid 50% in cash and 50% in common stock or deferred restricted stock units of the Company. Directors may elect to receive some or all of the cash retainer in common stock or deferred restricted stock units. In 2022, the Chairman of the Board received an additional $100 of annual compensation, paid 100% in common stock.

In the years ended December 31, 2022, 2021 and 2020, 106 thousand, 50 thousand and 79 thousand shares, respectively, of the Company’s common stock or restricted stock units were issued to non-employee directors under the Incentive Plan.