Investments in marketable securities consist of debt securities and equity investments. We classify all of our debt securities as available-for-sale (“AFS”). Except when fair value option is elected, AFS debt securities are recorded at fair value with unrealized gains or losses included in accumulated other comprehensive income (“AOCI”), net of applicable taxes. All equity investments are recorded at fair value with changes in fair value included in Investment and other income, net in our Consolidated Statements of Income.

In fiscal 2022, we have elected the fair value option for certain debt securities held within one of our affiliate investment portfolios for operational ease given the size and composition of this portfolio. All debt securities within this specific portfolio are recorded at fair value with changes in fair value included in Investment and other income, net in our Consolidated Statements of Income. We estimate the fair value of these securities using observed transaction prices, independent third-party pricing valuation vendors, and internal valuation models. AFS debt securities for which fair value option is elected are not subject to credit loss impairment. As of September 30, 2021, we held AFS debt securities for which fair value option was elected of $722 million. The difference between the aggregate fair value and the aggregate unpaid principal balance of long-term AFS debt securities for which the fair value option was elected was not significant.

	September 30, 2021
	Amortized		Unrealized		Unrealized			Fair
	cost		gains		losses			value
Available-for-sale debt securities:
U.S. government and agency obligations	$	448	$	5	$	(8	)	$	445
Foreign government and agency obligations		33		-		-			33
Municipal debt securities		9		2		-			11
Commercial paper		8		-		-			8
Corporate debt securities		638		19		(1	)		656
Mortgage-backed securities:
U.S. government agency		24		1		-			25
Non-agency residential		12		-		-			12
Non-agency commercial		71		3		(1	)		73
Asset-backed securities		88		3		-			91
Total available-for-sale debt securities	$	1,331	$	33	$	(10	)	$	1,354
Equity investments									3,481
Total investments in marketable securities								$	4,835

	March 31, 2021
	Amortized		Unrealized		Unrealized			Fair
	cost		gains		losses			value
Available-for-sale debt securities:
U.S. government and agency obligations	$	217	$	4	$	(10	)	$	211
Municipal debt securities		8		2		-			10
Commercial paper		196		-		-			196
Corporate debt securities		177		12		(2	)		187
Mortgage-backed securities:
U.S. government agency		31		1		-			32
Non-agency residential		1		-		-			1
Non-agency commercial		47		2		(2	)		47
Asset-backed securities		49		3		-			52
Total available-for-sale debt securities	$	726	$	24	$	(14	)	$	736
Equity investments									4,084
Total investments in marketable securities								$	4,820

A portion of our equity investments are investments in funds that are privately placed and managed by an open-end investment management company (the “Trust”). If we elect to redeem shares, the Trust will normally redeem all shares for cash, but may, in unusual circumstances, redeem amounts exceeding the lesser of $250 thousand or 1 percent of the Trust’s asset value by payment in kind of securities held by the respective fund during any 90-day period.

We also invest in actively traded open-end mutual funds. Redemptions are subject to normal terms and conditions as described in each fund’s prospectus.

For the six months ended September 30, 2021, non-cash investing activities related to in-kind redemptions and subsequent purchases amounted to $1.1 billion. There were no non-cash investing activities related to in-kind redemptions for the three months ended September 30, 2021.

Available-for-sale debt securities in a continuous loss position for less than twelve months and greater than twelve months were not significant as of September 30, 2021 and March 31, 2021.

An allowance for credit losses is established when it is determined that a credit loss has occurred. As of September 30, 2021, management determined that credit losses did not exist for securities in an unrealized loss position. This analysis considered a variety of factors including, but not limited to, performance indicators of the issuer, default rates, industry analyst reports, credit ratings, and other relevant information, which indicated that contractual cash flows are expected to occur.

The following table represents gains and losses on our investments in marketable securities presented in our Consolidated Statements of Income:

	Three months ended					Six months ended
	September 30,					September 30,
	2021			2020		2021		2020
Available-for-sale debt securities:
Unrealized (losses) gains for securities for which the fair value option was elected	$	(2	)	$	-	$	7	$	-
Realized gains	$	-		$	3	$	-	$	17

Equity investments:
Unrealized (losses) gains	$	(26	)	$	39	$	58	$	139
Realized gains on sales	$	-		$	1	$	22	$	12

The amortized cost and fair value by contractual maturities of available-for-sale debt securities are summarized in the following table. Actual maturities may differ from contractual maturities because certain borrowers have the right to call or prepay certain obligations.

	September 30, 2021
	Amortized cost		Fair value
Available-for-sale debt securities:
Due within 1 year	$	28	$	28
Due after 1 year through 5 years		471		477
Due after 5 years through 10 years		398		405
Due after 10 years		239		243
Mortgage-backed and asset-backed securities ¹		195		201
Total	$	1,331	$	1,354