Financial Instruments

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



	June 27, 2015									March 28, 2015
(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	$	304,935	$	—	$	—		$	304,935	$	235,583	$	—	$	—		$	235,583
Financial institution
securities	290,000		—		—			290,000		304,999		—		—			304,999
Non-financial institution
securities	425,413		44		(80		)	425,377		429,005		25		(6		)	429,024
Auction rate securities	10,500		—		(91		)	10,409		10,500		—		(188		)	10,312
Municipal bonds	53,839		552		(338		)	54,053		49,064		744		(152		)	49,656
U.S. government and
agency securities	575,867		142		(46		)	575,963		757,954		91		(129		)	757,916
Foreign government and
agency securities	201,045		—		—			201,045		197,932		—		—			197,932
Mortgage-backed securities	1,091,058		6,358		(9,467		)	1,087,949		1,075,730		8,942		(4,496		)	1,080,176
Asset-backed securities	219,682		958		(331		)	220,309		211,487		1,130		(159		)	212,458
Debt mutual funds	101,350		—		(7,002		)	94,348		101,350		—		(6,150		)	95,200
Bank loans	98,564		1,350		(79		)	99,835		98,131		29		(60		)	98,100
Commercial mortgage-
backed securities	105,119		178		(610		)	104,687		—		—		—			—
	$	3,477,372	$	9,582	$	(18,044	)	$	3,468,910	$	3,471,735	$	10,961	$	(11,340	)	$	3,471,356

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 June 27, 2015 and March 28, 2015:



	June 27, 2015
	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	$	31,065	$	(80	)	$	—	$	—		$	31,065	$	(80	)
Auction rate securities	—		—			10,409		(91		)	10,409		(91		)
Municipal bonds	21,356		(266		)	1,852		(72		)	23,208		(338		)
U.S. government and
agency securities	66,802		(46		)	—		—			66,802		(46		)
Mortgage-backed securities	734,577		(8,275		)	43,349		(1,192		)	777,926		(9,467		)
Asset-backed securities	84,268		(331		)	—		—			84,268		(331		)
Debt mutual fund	38,569		(1,431		)	55,779		(5,571		)	94,348		(7,002		)
Bank loans	56,551		(69		)	10,293		(10		)	66,844		(79		)
Commercial mortgage-
backed securities	45,045		(579		)	545		(31		)	45,590		(610		)
	$	1,078,233	$	(11,077	)	$	122,227	$	(6,967	)	$	1,200,460	$	(18,044	)



	March 28, 2015
	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	$	7,190	$	(6	)	$	—	$	—		$	7,190	$	(6	)
Auction rate securities	—		—			10,312		(188		)	10,312		(188		)
Municipal bonds	10,014		(94		)	1,931		(58		)	11,945		(152		)
U.S. government and
agency securities	451,296		(129		)	—		—			451,296		(129		)
Mortgage-backed securities	448,770		(3,169		)	49,207		(1,327		)	497,977		(4,496		)
Asset-backed securities	75,009		(159		)	—		—			75,009		(159		)
Debt mutual funds	38,608		(1,392		)	56,592		(4,758		)	95,200		(6,150		)
Bank loans	65,085		(60		)	—		—			65,085		(60		)
	$	1,095,972	$	(5,009	)	$	118,042	$	(6,331	)	$	1,214,014	$	(11,340	)

As of June 27, 2015, the gross unrealized losses that had been outstanding for less than twelve months were primarily related to mortgage-backed securities and debt mutual funds due to the general rising of the interest-rate environment and foreign currency movement, although the percentage of such losses to the total estimated fair value of the mortgage-backed securities and debt mutual funds 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 June 27, 2015 and March 28, 2015 were temporary in nature as evidenced by the fluctuations in the gross unrealized losses within the investment categories. These investments are highly rated by the credit rating agencies, there have been no defaults on any of these securities and we have received interest payments as they become due. Additionally, in the past several years a portion of the Company's investment in 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 June 27, 2015 and March 28, 2015. 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 Company also believes that it will be able to collect both principal and interest amounts due to the Company at maturity, given the high credit quality of these investments and any related underlying collateral.

The amortized cost and estimated fair value of marketable debt securities (financial institution securities, non-financial institution securities, auction rate securities, municipal bonds, U.S. and foreign government and agency securities, asset-backed securities, bank loans, mortgage-backed securities 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.



	June 27, 2015
(In thousands)	Amortized Cost		Estimated Fair Value
Due in one year or less	$	1,373,464	$	1,373,607
Due after one year through five years	367,169		367,111
Due after five years through ten years	300,178		300,357
Due after ten years	1,030,276		1,028,552
	$	3,071,087	$	3,069,627

As of June 27, 2015, $1.54 billion of marketable debt securities with contractual maturities of greater than one year were classified as short-term investments. Additionally, the above table did not include investments in money market and mutual funds because these funds do not have specific contractual maturities.

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



	Three Months Ended
(In thousands)	June 27, 2015			June 28, 2014
Proceeds from sale of available-for-sale securities	$	66,041		$	59,581
Gross realized gains on sale of available-for-sale securities	$	359		$	837
Gross realized losses on sale of available-for-sale securities	(129		)	(167		)
Net realized gains on sale of available-for-sale securities	$	230		$	670
Amortization of premiums on available-for-sale securities	$	6,468		$	6,233

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