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Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2025

Stockholders' Equity

Schedule of common stock reserved for issuance, on an as-converted basis

​

​	​	​	​	​
​		September 30,		December 31,
​	​	2025	​	2024
Stock options issued and outstanding		20,090,359		9,458,788
RSUs issued and outstanding	​	2,670,905	​	—
Shares available for grant under the 2024 Equity Incentive Plan	​	930,301	​	6,893,517
Shares available for grant under the 2024 Employee Stock Purchase Plan	​	1,009,440	​	650,000
Shares available for grant under the ACELYRIN, Inc. 2023 Equity Incentive Plan	​	6,448,105	​	—
Shares available for grant under the 2024 Performance Option Plan	​	199,856	​	92,800
Total		31,348,966		17,095,105

Schedule of summarizes the activity for the company's restricted common stock

​

​	​	​	​	​	​
​		​		Weighted-
​	​	​	​	Average
​	​	Number of	​	Grant Date
​	​	Shares	​	Fair Value
Unvested as of December 31, 2024		2,583	​	$	2.90
Vested		(2,583)	​	$	2.90
Unvested as of September 30, 2025		—	​	$	—

​

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Tabular disclosure of common stock reserved for issuance, on an as-converted basis.

+ References

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Tabular disclosure of the changes in outstanding nonvested restricted stock shares.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Subparagraph (c)
-Paragraph 2
-SubTopic 10
-Topic 718
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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