As of September 30, 2024, the Align Technology, Inc. 2005 Incentive Plan, as amended, has a total reserve of 32,168,895 shares, of which 3,398,202 shares are available for issuance.

The stock-based compensation related to our stock-based awards and employee stock purchase plan for the three and nine months ended September 30, 2024 and 2023 is as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2024		2023		2024		2023
Cost of net revenues	$	3,070	$	1,974	$	7,716	$	5,682
Selling, general and administrative	34,937		29,739		97,705		87,432

Research and development	11,032		7,889		29,434		22,083
Total stock-based compensation	$	49,039	$	39,602	$	134,855	$	115,197

The fair value of RSUs is based on our closing stock price on the date of grant. RSUs granted generally vest over a period of four years. A summary for the nine months ended September 30, 2024 is as follows:


	Number of Shares Underlying RSUs (in thousands)	Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Unvested as of December 31, 2023	736	$	367.63
Granted	638	309.22
Vested and released	(254)	370.69
Forfeited	(56)	345.74
Unvested as of September 30, 2024	1,064	$	333.03	1.6	$	270,565

As of September 30, 2024, we expect to recognize $254.4 million of total unamortized compensation costs, net of estimated forfeitures, related to RSUs over a weighted average period of 2.7 years.

We grant MSUs to members of senior management. Each MSU represents the right to one share of our common stock. The actual number of MSUs which will be eligible to vest will be based on the performance of Align’s stock price relative to the performance of a stock market index over the vesting period. MSUs vest over a period of three years and the maximum number of shares eligible to vest in the future is 250% of the MSUs initially granted.

The following table summarizes the MSU performance activity for the nine months ended September 30, 2024:


	Number of Shares Underlying MSUs (in thousands)	Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Unvested as of December 31, 2023	158	$	811.06
Granted	83	617.79
Vested and released 1	(32)	1,102.09
Forfeited	(5)	1,102.09
Unvested as of September 30, 2024	204	$	679.52	1.6	$	51,876

1 Includes MSUs vested during the period below 100% of the original grant as actual shares released is based on Align’s stock performance relative to a market index over the vesting period.

As of September 30, 2024, we expect to recognize $67.2 million of total unamortized compensation costs, net of estimated forfeitures, related to MSUs over a weighted average period of 1.6 years.

Our PSUs typically include a service and performance condition. We recognize share-based compensation expense for PSUs if it is probable that the performance condition will be achieved.

The following table summarizes the PSU performance activity for the nine months ended September 30, 2024:


	Number of Shares Underlying PSUs (in thousands)		Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Unvested as of December 31, 2023	$	5	$	201.63
Granted	6		206.36
Vested and released	—		—
Forfeited	—		—
Unvested as of September 30, 2024	$	11	$	204.33	1.4	$	2,805

As of September 30, 2024, we expect to recognize $1.2 million of total unamortized compensation costs, net of estimated forfeitures, related to PSUs over a weighted average period of 1.4 years.

As of September 30, 2024, we have 1,875,920 shares available for future issuance under the Align Technology, Inc. 2010 Employee Stock Purchase Plan (as amended and restated, the “2010 Purchase Plan”).

The fair value of the option component of the 2010 Purchase Plan shares was estimated at the grant date using the Black-Scholes option pricing model with the following weighted average assumptions:


	Nine Months Ended September 30,
		2024			2023
Expected term (in years)		1.3			1.2
Expected volatility		49.2		%	56.2		%
Risk-free interest rate		4.6		%	4.9		%
Expected dividends		—			—
Weighted average fair value at grant date		$	94.70		$	133.53

As of September 30, 2024, we expect to recognize $17.1 million of total unamortized compensation costs related to future employee stock purchases over a weighted average period of 0.9 years.