	March 31,		December 31,
	2020		2019
Partnership interests in private equity funds	$	61.2	$	76.7
Marketable equity securities		29.8		37.9
Non-marketable equity securities		84.5		45.5
Total investments	$	175.5	$	160.1

Realized and unrealized gains and losses for our equity securities are as follows (in millions):

	Three Months Ended March 31,
	2020			2019
Unrealized (losses) gains on equity securities held as of the end of the period	$	(11.1	)	$	7.3
Realized gains (losses) for equity securities sold during the period		1.4			(0.2	)
Total (losses) gains recognized in other (expense) income, net	$	(9.7	)	$	7.1

On February 27, 2020, we entered into a Series A Convertible Share Purchase Agreement with SILAC, Inc. (“SILAC”), pursuant to which we acquired 40 million shares of Series A convertible preferred stock of SILAC for a purchase price of $40.0 million. Mr. William C. Stone, our Chairman of the Board of Directors and Chief Executive Officer, has an economic interest in SILAC and is a member of its board of directors. Accordingly, the transaction constitutes a “related person transaction” under our related person transaction policy. Our audit committee and the independent members of our Board of Directors authorized and approved the transaction. Mr. Stone did not participate in the Board of Directors’ consideration of the transaction. The investment is classified as a non-marketable equity security.

Authoritative accounting guidance on fair value measurements establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs for which little or no market data exists, therefore requiring an entity to develop its own assumptions.

As of March 31, 2020 and December 31, 2019, we held certain investment assets and certain liabilities that are required to be measured at fair value on a recurring basis. These investments include money market funds and marketable equity securities where fair value is determined using quoted prices in active markets. Accordingly, the fair value measurements of these investments have been classified as Level 1 in the tables below. Investments for which we elected net asset value as a practical expedient for fair value and investments measured using the fair value measurement alternative are excluded from the tables below. Fair value for deferred compensation liabilities that are credited with deemed gains or losses of the underlying hypothetical investments, primarily equity securities, have been classified as Level 1 in the tables below.

The following tables present assets and liabilities measured at fair value on a recurring basis (in millions):

				Fair Value Measurements at Reporting Date Using
	March 31, 2020			Quoted prices in Active Markets for Identical Assets (Level 1)			Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market funds (1)	$	658.0		$	658.0		$	—	$	—
Marketable equity securities (2)		29.8			29.8			—		—
Deferred compensation liabilities (3)		(14.1	)		(14.1	)		—		—
Total	$	673.7		$	673.7		$	—	$	—

				Fair Value Measurements at Reporting Date Using
	December 31, 2019			Quoted prices in Active Markets for Identical Assets (Level 1)			Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market funds (1)	$	1,051.1		$	1,051.1		$	—	$	—
Marketable equity securities (2)		37.9			37.9			—		—
Deferred compensation liabilities (3)		(20.8	)		(20.8	)		—		—
Total	$	1,068.2		$	1,068.2		$	—	$	—

During the three months ended March 31, 2020, the fair value of our non-marketable equity securities was adjusted downward by $1.0 million. During the three months ended March 31, 2019, the fair value of our non-marketable equity securities was adjusted upward by $0.4 million.

We have partnership interests in various private equity funds that are not included in the tables above. Our investments in private equity funds were $61.2 million and $76.7 million at March 31, 2020 and December 31, 2019, respectively, of which $57.1 million and $72.1 million, respectively, were measured using net asset value as a practical expedient for fair value and $4.1 million and $4.6 million, respectively, were accounted for under the equity method of accounting. The investments in private equity funds represent underlying investments in domestic and international markets across various industry sectors. At March 31, 2020 and December 31, 2019, one of our investments in private equity funds, representing 74% and 75%, respectively, of the total value of the private equity fund investments, was primarily invested in the energy sector and real estate. We have no management rights associated with our partnership interests in this fund and withdrawals from this fund are subject to general partner consent. This fund has a termination date in 2020 with an optional one-year extension at the discretion of the general partner. We expect to receive distributions from this fund upon liquidation of the underlying investments over the next several years, however the exact timing of the distributions is unknown. We have no unfunded commitments related to this fund. Future capital commitments related to our other private equity fund investments were approximately $1.6 million as of March 31, 2020 and December 31, 2019, respectively.

Generally, our investments in private equity funds are non-transferable or are subject to long holding periods, and withdrawals from the private equity firm partnerships are typically not permitted. Even when transfer restrictions do not apply, there is generally no public market for the securities. Therefore, we may not be able to sell the securities at a time when we desire to do so. We may not always be able to sell those investments at the same or higher prices than we paid for them. As of March 31, 2020, we did not have plans to sell any of these investments. The maximum risk of loss related to our private equity fund investments is limited to the carrying value of its investments in the entities plus any future capital commitments, which include future commitments that we believe are unlikely to be called by the general partner.