Financial Instruments

The following is a summary of cash equivalents and available-for-sale securities as of the end of the periods presented:



	April 1, 2017									April 2, 2016
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Money market funds	$	298,307	$	—	$	—		$	298,307	$	232,698	$	—	$	—		$	232,698
Financial institution
securities	348,797		—		—			348,797		284,853		—		—			284,853
Non-financial institution
securities	409,109		647		(496		)	409,260		564,480		862		(230		)	565,112
Auction rate securities	—		—		—			—		10,500		—		(523		)	9,977
Municipal bonds	—		—		—			—		68,938		877		(133		)	69,682
U.S. government and
agency securities	130,749		8		(223		)	130,534		192,291		73		(71		)	192,293
Foreign government and
agency securities	322,172		—		(51		)	322,121		313,168		—		—			313,168
Mortgage-backed securities	1,186,732		3,527		(14,757		)	1,175,502		1,200,071		12,848		(5,380		)	1,207,539
Asset-backed securities	220,033		404		(686		)	219,751		216,068		1,151		(605		)	216,614
Debt mutual funds	101,350		—		(12,674		)	88,676		101,350		—		(9,449		)	91,901
Bank loans	153,281		839		(106		)	154,014		102,092		25		(102		)	102,015
Commercial mortgage-
backed securities	221,504		146		(3,679		)	217,971		207,847		432		(1,809		)	206,470
	$	3,392,034	$	5,571	$	(32,672	)	$	3,364,933	$	3,494,356	$	16,268	$	(18,302	)	$	3,492,322

Financial institution securities include securities issued or managed by financial institutions in various forms, such as commercial paper and time deposits. Substantially all time deposits were issued by institutions outside the U.S. as of April 1, 2017 and April 2, 2016.

The following tables show the fair values and gross unrealized losses of the Company's investments, aggregated by investment category, for individual securities that have been in a continuous unrealized loss position for the length of time specified, as of April 1, 2017 and April 2, 2016:



	April 1, 2017
	Less Than 12 Months					12 Months or Greater					Total
(In thousands)	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Non-financial institution securities	$	68,850	$	(492	)	$	1,022	$	(4	)	$	69,872	$	(496	)
U.S. government and
agency securities	64,895		(223		)	—		—			64,895		(223		)
Mortgage-backed securities	811,058		(11,872		)	139,931		(2,885		)	950,989		(14,757		)
Asset-backed securities	119,845		(651		)	4,689		(35		)	124,534		(686		)
Debt mutual funds	—		—			88,676		(12,674		)	88,676		(12,674		)
Bank loans	15,139		(106		)	—		—			15,139		(106		)
Foreign government and
agency securities	64,857		(51		)	—		—			64,857		(51		)
Commercial mortgage-
backed securities	165,393		(1,706		)	24,362		(1,973		)	189,755		(3,679		)
	$	1,310,037	$	(15,101	)	$	258,680	$	(17,571	)	$	1,568,717	$	(32,672	)



	April 2, 2016
	Less Than 12 Months					12 Months or Greater					Total
(In thousands)	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Non-financial institution securities	$	52,756	$	(230	)	$	—	$	—		$	52,756	$	(230	)
Auction rate securities	—		—			9,977		(523		)	9,977		(523		)
Municipal bonds	10,138		(44		)	3,867		(89		)	14,005		(133		)
U.S. government and
agency securities	84,024		(71		)	—		—			84,024		(71		)
Mortgage-backed securities	346,560		(3,916		)	114,285		(1,464		)	460,845		(5,380		)
Asset-backed securities	81,038		(502		)	20,793		(103		)	101,831		(605		)
Debt mutual funds	—		—			91,901		(9,449		)	91,901		(9,449		)
Bank loans	34,358		(31		)	42,832		(71		)	77,190		(102		)
Commercial mortgage-
backed securities	141,761		(878		)	2,150		(931		)	143,911		(1,809		)
	$	750,635	$	(5,672	)	$	285,805	$	(12,630	)	$	1,036,440	$	(18,302	)

As of April 1, 2017, the gross unrealized losses that had been outstanding for less than twelve months were primarily related to mortgage-backed securities due to the general rising of the interest-rate environment, although the percentage of such losses to the total estimated fair value of the mortgage-backed securities was relatively insignificant. The gross unrealized losses that had been outstanding for more than twelve months were primarily related to debt mutual funds and mortgage-backed securities, which were primarily due to the general rising of the interest-rate environment and foreign currency movement.

The Company reviewed the investment portfolio and determined that the gross unrealized losses on these investments as of April 1, 2017 and April 2, 2016 were temporary in nature as evidenced by the fluctuations in the gross unrealized losses within the investment categories, in particular within the debt mutual funds during the past few years. The Company's investment in mortgage-backed securities and commercial mortgage-backed securities are highly rated by the credit rating agencies and there have been no defaults on any of these securities, and we have received interest payments as they become due. Therefore, the Company believes that it will be able to collect both principal and interest amounts due to the Company. Additionally, in the past several years, a portion of the Company's investment in the auction rate securities and the mortgage-backed securities were redeemed or prepaid by the debtors at par. Furthermore, the aggregate of individual unrealized losses that had been outstanding for twelve months or more was not significant as of April 1, 2017 and April 2, 2016, the majority of which are related to debt mutual funds due to foreign currency and interest rate movement. The Company neither intends to sell these investments nor concludes that it is more-likely-than-not that it will have to sell them until recovery of their carrying values.

The amortized cost and estimated fair value of marketable debt securities (financial institution securities, non-financial institution securities, U.S. and foreign government and agency securities, mortgage-backed securities, asset-backed securities, bank loans and commercial mortgage-backed securities), by contractual maturity, are shown below. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations without call or prepayment penalties.



	April 1, 2017
(In thousands)	Amortized Cost		Estimated Fair Value
Due in one year or less	$	1,007,551	$	1,007,487
Due after one year through five years	491,907		489,627
Due after five years through ten years	293,184		292,691
Due after ten years	1,199,735		1,188,145
	$	2,992,377	$	2,977,950

As of April 1, 2017, $1.94 billion of marketable debt securities with contractual maturities of greater than one year were classified as short-term investments. Additionally, the above table does not include investments in money market and debt mutual funds because these funds do not have specific contractual maturities.

Certain information related to available-for-sale securities is as follows:



	Year Ended
(In thousands)	April 1, 2017			April 2, 2016			March 28, 2015
Proceeds from sale of available-for-sale securities	$	695,030		$	268,887		$	1,617,658
Gross realized gains on sale of available-for-sale securities	$	6,989		$	1,248		$	15,101
Gross realized losses on sale of available-for-sale securities	(3,457		)	(878		)	(3,223		)
Net realized gains on sale of available-for-sale securities	$	3,532		$	370		$	11,878
Amortization of premiums on available-for-sale securities	$	29,360		$	26,613		$	23,579

The cost of securities matured or sold is based on the specific identification method.