Equity Securities

3 Months Ended

Mar. 31, 2025

Investments, Debt and Equity Securities [Abstract]

Note 4 – Equity Securities

Investments in equity securities, by accounting classification, are summarized as follows:


(in millions)	March 31, 2025		December 31, 2024
Marketable equity securities	$	367.4	$	386.8
Non-marketable equity securities		216.6		202.4
Equity method investments		102.7		102.1
	$	686.7	$	691.3

Investments in marketable equity securities are summarized as follows:


(in millions)	Cost		Unrealized losses			Estimated fair value
March 31, 2025
Common stocks	$	390.9	$	(35.6	)	$	355.3
Preferred stocks		12.0		0.1			12.1
	$	402.9	$	(35.5	)	$	367.4
December 31, 2024
Common stocks	$	397.3	$	(22.6	)	$	374.7
Preferred stocks		12.0		0.1			12.1
	$	409.3	$	(22.5	)	$	386.8

Net losses of $7.0 million and net gains of $10.9 million resulting from changes in the fair values of marketable equity securities were recognized for the three months ended March 31, 2025 and 2024, respectively, which included net unrealized losses of $6.7 million and net unrealized gains of $10.5 million on securities still held at March 31, 2025 and 2024, respectively.

A summary of the changes in the carrying amounts of non-marketable equity securities, which primarily relate to the Company's venture investment portfolio, for the three months ended March 31, 2025 and 2024, is as follows:


	Three Months Ended March 31,
(in millions)	2025			2024
Carrying amount, beginning of period	$	202.4		$	224.1
Net additions		15.0			1.8
Gross unrealized gains		—			0.2
Gross unrealized losses and impairments		(0.8	)		—
Carrying amount, end of period	$	216.6		$	226.1

Cumulative gross unrealized gains and cumulative gross unrealized losses and impairments related to non-marketable equity securities at March 31, 2025 and December 31, 2024, are summarized as follows:


(in millions)	March 31, 2025		December 31, 2024
Cumulative gross unrealized gains	$	244.8	$	244.8
Cumulative gross unrealized losses and impairments	$	352.4	$	351.6