The Company awards equity-based compensation to employees and directors, which is recognized in the statements of income based on the grant-date fair value of the award. The Company uses the straight-line method for recording compensation expense over a vesting period generally up to four years with either graded or cliff vesting. Stock compensation expense recognized during the period is based on the value of the portion of equity-based awards that is ultimately expected to vest during the period reduced by the expense on unvested awards forfeited during the period.

On May 3, 2023, the stockholders of the Company approved the adoption of the Gibraltar Industries, Inc. Amended and Restated 2018 Equity Incentive Plan (the "Amended 2018 Plan") which increases the total number of shares available for issuance by the Company from 1,000,000 shares to 1,550,000 shares. In addition, 81,707 shares that were unissued and available for grant under the Gibraltar Industries, Inc. 2015 Equity Incentive Plan (the "2015 Plan") were consolidated with the Amended 2018 Plan. No further grants will be made under the 2015 Plan. The Amended 2018 Plan allows the Company to grant equity-based incentive compensation awards, in the form of non-qualified options, restricted shares, restricted stock units, performance shares, performance stock units, and stock rights to eligible participants.

On May 4, 2022, the stockholders of the Company approved the adoption of the Gibraltar Industries, Inc. Amended and Restated 2016 Stock Plan for Non-Employee Directors ("Non-Employee Directors Plan") which increases the total number of shares for issuance by the Company thereunder from 100,000 shares to 200,000 shares, allows the Company to grant awards of shares of the Company's common stock to current non-employee Directors of the Company, and permits the Directors to defer receipt of such shares pursuant to the terms of the Non-Employee Directors Plan.

At December 31, 2023, approximately 885,000 shares were available for issuance under the Amended 2018 Plan as incentive stock options or other stock awards, and approximately 86,000 shares were available for issuance under the Non-Employee Directors Plan as awards of shares of the Company's common stock.

The compensation cost for employee and non-employee director equity-based compensation plans for all current and prior year awards granted along with the related tax benefits recognized during the years ended December 31 (in thousands) were as follows:

The following table provides the number of stock units and common stock granted during the years ended December 31, along with the weighted-average grant-date fair value of each award:


	2023			2022			2021
Awards	Number of Awards	Weighted Average Grant Date Fair Value		Number of Awards	Weighted Average Grant Date Fair Value		Number of Awards	Weighted Average Grant Date Fair Value


Deferred stock units	6,351	$	54.33	2,460	$	42.69	7,536	$	83.58
Common stock	8,468	$	54.33	15,652	$	42.49	2,512	$	83.58
Restricted stock units	99,820	$	61.93	132,430	$	43.92	72,243	$	79.28
Performance stock units (1)	85,323	$	53.22	108,464	$	47.00	62,778	$	87.84

(1) The Company’s performance stock units (“PSUs”) represent shares granted for which the final number of shares earned depends on financial performance. The number of shares to be issued may vary between 0% and 200% of the number of PSUs granted depending on the relative achievement to targeted thresholds. The Company's PSUs with a financial performance condition are based on the Company’s return on invested capital (“ROIC”) over a one-year period performance period.

No options were granted during the years ended December 31, 2023, 2022 and 2021. The Company determines the fair value of stock options granted based on the Black-Scholes option pricing model on the date of grant, and the expected stock volatility is based on volatility of the Company’s stock price using a historical period commensurate with the expected life of the options.

At December 31, 2023, the Company has one grant of options outstanding. The following table summarizes the Company's outstanding and exercisable options at December 31, 2023:


Exercise Price	Options Outstanding	Weighted Average Remaining Contractual Life (in years)	Weighted Average Exercise Price		Options Exercisable	Weighted Average Exercise Price
$39.55	5,000	3.26	$	39.55	5,000	$	39.55


	Options	Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in years)	Aggregate Intrinsic Value
Balance at January 1, 2021	41,500	$	29.38

Exercised	(36,500)	$	27.99

Balance at December 31, 2021	5,000	$	39.55


Exercised	—	$	—
Balance at December 31, 2022	5,000	$	39.55
Exercised	—	$	—
Balance at December 31, 2023	5,000	$	39.55	3.26	$	197,150

The aggregate intrinsic value in the preceding table represents the total pre-tax intrinsic value, based on the $78.98 per share market price of the Company’s common stock as of December 31, 2023, which would have been received by the option holder had the option holder exercised the options as of that date.

The following table summarizes information about non-vested restricted stock units and performance stock units (that will convert to shares upon vesting) and common stock:


	Restricted Stock Units	Weighted Average Grant Date Fair Value		Common Stock	Weighted Average Grant Date Fair Value		Performance Stock Units	Weighted Average Grant Date Fair Value		Deferred Stock Units (2)	Weighted Average Grant Date Fair Value
Balance at December 31, 2022	235,370	$	49.87	—	$	—	211,368	$	50.96	40,350	$	45.16
Granted	99,820	$	61.93	8,468	$	54.33	85,323	$	53.22	6,351	$	54.33
Adjustments (1)	—	$	—	—	$	—	(70,610)	$	50.72	—	$	—
Vested	(77,312)	$	53.37	(8,468)	$	54.33	(71,106)	$	51.74	(2,222)	$	36.47
Forfeited	(24,908)	$	50.99	—	$	—	(18,729)	$	49.69	—	$	—
Balance at December 31, 2023	232,970	$	53.75	—	$	—	136,246	$	52.27	44,479	$	46.90

(1) (i) 40,610 units of the Company's PSUs granted in 2022 were adjusted in the first quarter of 2023 to reflect 60.5% of the target amount granted based on the Company's actual ROIC compared to ROIC target for the performance period ended December 31, 2022; and (ii) 30,000 units of the Company's TSR PSUs granted in 2020 for which the performance condition was not achieved and the PSUs were adjusted in the first quarter of

2023 to reflect zero earned as the threshold level of achievement was not met based on performance criteria as defined in the respective awards over a three-year performance period which ended March 1, 2023.

The fair value of the common stock, restricted stock units, and deferred stock units, as well as the performance stock units with a financial performance condition granted during the three years ended December 31, 2023 was based on the Company's stock price at grant date of the award.

The following table sets forth the aggregate intrinsic value of options exercised and aggregate fair value of restricted stock units and restricted shares that vested during the years ended December 31 (in thousands):


	2023		2022		2021
Aggregate intrinsic value of options exercised	$	—	$	—	$	2,103
Aggregate fair value of vested restricted stock units	$	4,740	$	3,920	$	6,320
Aggregate fair value of vested common stock	$	460	$	665	$	370
Aggregate fair value of vested performance stock units	$	3,999	$	6,729	$	9,080
Aggregate fair value of vested deferred stock units	$	345	$	105	$	630

As of December 31, 2023, there was $13.1 million of total unrecognized compensation cost related to non-vested restricted and performance stock units. That cost is expected to be recognized over a weighted average period of 2.0 years.

The Company's equity-based awards that are settled in cash are the awards under the Management Stock Purchase Plan (the "MSPP") which is authorized under the Company's equity incentive plans. The MSPP provides participants the ability to defer a portion of their compensation, convertible to unrestricted investments, restricted stock units, or a combination of both, or defer a portion of their directors’ fees, convertible to restricted stock units. Employees eligible to defer a portion of their compensation also receive a company-matching award in restricted stock units equal to a percentage of their deferred compensation.

The deferrals and related company match are credited to an account that represents a share-based liability. The portion of the account deferred to unrestricted investments is measured at fair market value of the unrestricted investments, and the portion of the account deferred to restricted stock units and company-matching restricted stock units is measured at a 200-day average of the Company's stock price. The account will be converted to and settled in cash payable to participants upon retirement or a termination of their service to the Company.

Total MSPP liabilities recorded on the consolidated balance sheet as of December 31, 2023 were $20.0 million, of which $2.0 million was included in current accrued expenses and $18.0 million was included in non-current liabilities. Total MSPP liabilities recorded on the consolidated balance sheet as of December 31, 2022 were $15.4 million, of which $2.3 million was included in current accrued expenses and $13.1 million was included in non-current liabilities. The value of the restricted stock units within the MSPP liabilities was $17.3 million and $13.4 million at December 31, 2023 and 2022, respectively.

The following table provides the number of restricted stock units credited to active participant accounts, balance of vested and unvested restricted stock units within active participant accounts, payments made with respect to MSPP liabilities and MSPP expense during years ended December 31:


	2023		2022		2021
Restricted stock units credited	48,921		12,365		30,475
Restricted stock units balance, vested and unvested	199,946		158,644		223,892
Share-based liabilities paid (in thousands)	$	2,392	$	3,689	$	4,915
MSPP expense (recovery) (in thousands)	$	4,710	$	(4,459)	$	6,034