Investments

Debt Securities

As of October 31, 2018, debt securities consisted of the following (in thousands):



	Amortized Cost		Unrealized Gains		Unrealized Losses			Aggregate Fair Value
U.S. agency obligations	$	188,241	$	1	$	(375	)	$	187,867
U.S. treasury securities	376,887		—		(437		)	376,450
Corporate bonds	402,034		6		(1,027		)	401,013
Commercial paper	283,260		—		—			283,260
	$	1,250,422	$	7	$	(1,839	)	$	1,248,590
Included in cash and cash equivalents	$	239,214	$	—	$	—		$	239,214
Included in marketable securities	$	1,011,208	$	7	$	(1,839	)	$	1,009,376

As of January 31, 2018, debt securities consisted of the following (in thousands):



	Amortized Cost		Unrealized Gains		Unrealized Losses			Aggregate Fair Value
U.S. agency obligations	$	683,551	$	—	$	(1,127	)	$	682,424
U.S. treasury securities	797,977		—		(1,142		)	796,835
Corporate bonds	470,259		16		(1,154		)	469,121
Commercial paper	602,727		—		—			602,727
	$	2,554,514	$	16	$	(3,423	)	$	2,551,107
Included in cash and cash equivalents	$	417,613	$	—	$	(1	)	$	417,612
Included in marketable securities	$	2,136,901	$	16	$	(3,422	)	$	2,133,495

We do not believe the unrealized losses represent other-than-temporary impairments based on our evaluation of available evidence, which includes our intent to hold these investments to maturity as of October 31, 2018. The unrealized losses on debt securities that have been in a net loss position for 12 months or more were not material as of October 31, 2018. We classify our debt securities as available-for-sale at the time of purchase and reevaluate such classification as of each balance sheet date. We consider all debt securities as available for use in current operations, including those with maturity dates beyond one year, and therefore classify these securities as current assets in the accompanying condensed consolidated balance sheets. Debt securities included in Marketable securities on the condensed consolidated balance sheets consist of securities with original maturities at the time of purchase greater than three months, and the remainder of the securities is included in Cash and cash equivalents. We sold $3 million and $33 million of our debt securities during the three months ended October 31, 2018 and 2017, respectively, and $946 million and $223 million of our debt securities during the nine months ended October 31, 2018 and 2017, respectively. The realized gains and losses from the sales were immaterial.

Equity Investments

Money market funds and marketable equity investments are investments with readily determinable fair values. Non-marketable equity investments consist of investments in privately held companies without readily determinable fair values.

Equity investments consisted of the following (in thousands):



	Condensed Consolidated Balance Sheets Location	October 31, 2018		January 31, 2018
Money market funds	Cash and cash equivalents	$	194,272	$	551,804
Marketable equity investments	Marketable securities	32,333		—
Non-marketable equity investments	Other assets	27,661		28,005
		$	254,266	$	579,809

There were no adjustments made to the carrying value of the non-marketable equity investments as measured under the measurement alternative during the three and nine months ended October 31, 2018. Realized and unrealized gains and losses associated with our equity investments consisted of the following (in thousands):



	Three Months Ended October 31,					Nine Months Ended October 31,
	2018		2017			2018		2017
Net realized gains (losses) recognized on equity investments sold	$	8,193	$	194		$	8,193	$	720
Net unrealized gains (losses) recognized on equity investments held	20,333		(100		)	20,333		(100		)
Total net gains (losses) recognized in other income (expense), net	$	28,526	$	94		$	28,526	$	620