Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2023

Financial Instruments Pledged as Collateral [Abstract]

Schedule of Short-term and Long-term Investment Marketable Securities by Security Type

Investments

Cullinan recognized its short-term and long-term investments by security type at September 30, 2023 as follows:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Short-term investments
U.S. government notes	$	193,069	$	1	$	(131	)	$	192,939
Corporate notes		148,890		13		(612	)		148,291
Asset-backed securities		60,574		—		(221	)		60,353
Total short-term investments		402,533		14		(964	)		401,583
Long-term investments
Corporate notes		13,646		—		(101	)		13,545
Total long-term investments		13,646		—		(101	)		13,545
Total investments	$	416,179	$	14	$	(1,065	)	$	415,128

The Company recognized its short-term and long-term investments by security type at December 31, 2022 as follows:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Short-term investments
Corporate notes	$	244,498	$	11	$	(1,743	)	$	242,766
U.S. government notes		34,029		—		(290	)		33,739
Commercial paper		18,035		3		(13	)		18,025
Asset-backed securities		16,625		—		(15	)		16,610
Total short-term investments		313,187		14		(2,061	)		311,140
Long-term investments
Corporate notes		81,436		18		(572	)		80,882
Total long-term investments		81,436		18		(572	)		80,882
Total investments	$	394,623	$	32	$	(2,633	)	$	392,022

Summary of Fair Value of Financial Assets Measured at Fair Value on a Recurring Basis

The following table sets forth the fair value of Cullinan’s financial assets that were measured at fair value on a recurring basis as of September 30, 2023:

	Level 1		Level 2		Level 3		Total
	(in thousands)
Short-term investments
U.S. government notes	$	—	$	192,939	$	—	$	192,939
Corporate notes		—		148,291		—		148,291
Asset-backed securities		—		60,353		—		60,353
Total short-term investments		—		401,583		—		401,583
Long-term investments
Corporate notes		—		13,545		—		13,545
Total long-term investments		—		13,545		—		13,545
Total investments	$	—	$	415,128	$	—	$	415,128

The following table sets forth the fair value of the Company’s financial assets that were measured at fair value on a recurring basis as of December 31, 2022:

	Level 1		Level 2		Level 3		Total
	(in thousands)
Short-term investments
Corporate notes	$	—	$	242,766	$	—	$	242,766
U.S. government notes		—		33,739		—		33,739
Commercial paper		—		18,025		—		18,025
Asset-backed securities		—		16,610		—		16,610
Total short-term investments		—		311,140		—		311,140
Long-term investments
Corporate notes		—		80,882		—		80,882
Total long-term investments		—		80,882		—		80,882
Total investments	$	—	$	392,022	$	—	$	392,022