Financial Instruments (Tables)

6 Months Ended

Jun. 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 June 30, 2023 as follows:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Short-term investments
Corporate notes	$	202,320	$	—	$	(1,113	)	$	201,207
U.S. government notes		74,708		3		(86	)		74,625
Asset-backed securities		74,434		—		(302	)		74,132
Total short-term investments		351,462		3		(1,501	)		349,964
Long-term investments
Corporate notes		18,758		—		(127	)		18,631
Total long-term investments		18,758		—		(127	)		18,631
Total investments	$	370,220	$	3	$	(1,628	)	$	368,595

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 June 30, 2023:

	Level 1		Level 2		Level 3		Total
	(in thousands)
Short-term investments
Corporate notes	$	—	$	201,207	$	—	$	201,207
U.S. government notes		—		74,625		—		74,625
Asset-backed securities		—		74,132		—		74,132
Total short-term investments		—		349,964		—		349,964
Long-term investments
Corporate notes		—		18,631		—		18,631
Total long-term investments		—		18,631		—		18,631
Total investments	$	—	$	368,595	$	—	$	368,595

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

As of June 30, 2023 and December 31, 2022, the fair values of Cullinan's cash and cash equivalents, prepaid expenses and other current assets, accounts payable, accrued expenses and other current liabilities approximated their carrying values due to the short-term nature of these instruments.