Marketable Securities

All of our cash equivalents and marketable securities are classified as “available-for-sale” securities. These securities are reported at fair value, with the related unrealized gains and losses included in accumulated other comprehensive income, a component of stockholders’ equity, net of tax, and net realized gains and losses recorded in other income, net, on the Condensed Consolidated Statements of Income.

We performed an impairment review of our investment portfolio as of October 26, 2014. Based on our quarterly impairment review and having considered the guidance in the relevant accounting literature, we concluded that our investments were appropriately valued and that no other than temporary impairment charges were necessary on our portfolio as of October 26, 2014.

The following is a summary of cash equivalents and marketable securities at October 26, 2014 and January 26, 2014:



	October 26, 2014
	Amortized Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value
	(In thousands)
Corporate debt securities	$	1,954,162	$	3,418	$	(520	)	$	1,957,060
Debt securities of United States government agencies	585,391		787		(53		)	586,125
Debt securities issued by United States Treasury	575,188		2,891		(66		)	578,013
Asset-backed securities	437,791		159		(199		)	437,751
Mortgage-backed securities issued by United States government-sponsored enterprises	273,812		4,590		(718		)	277,684
Foreign government bonds	85,259		135		(16		)	85,378
Money market funds	72,881		—		—			72,881
Total	$	3,984,484	$	11,980	$	(1,572	)	$	3,994,892
Classified as:
Cash equivalents								$	148,778
Marketable securities								3,846,114
Total								$	3,994,892



	January 26, 2014
	Amortized Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value
	(In thousands)
Corporate debt securities	$	1,762,833	$	1,837	$	(945	)	$	1,763,725
Debt securities of United States government agencies	1,012,740		848		(261		)	1,013,327
Debt securities issued by United States Treasury	495,889		621		(57		)	496,453
Money market funds	307,865		—		—			307,865
Asset-backed securities	258,017		15		(315		)	257,717
Mortgage-backed securities issued by United States government-sponsored enterprises	185,594		3,837		(725		)	188,706
Foreign government bonds	64,955		20		(120		)	64,855
Total	$	4,087,893	$	7,178	$	(2,423	)	$	4,092,648
Classified as:
Cash equivalents								$	572,425
Marketable securities								3,520,223
Total								$	4,092,648

The following table provides the breakdown of the investments with unrealized losses at October 26, 2014:



	Less than 12 months					12 months or greater					Total
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
	(In thousands)
Corporate debt securities	$	698,851	$	(83	)	$	1,258,209	$	(437	)	$	1,957,060	$	(520	)
Debt securities of United States government agencies	278,703		(8		)	307,422		(45		)	586,125		(53		)
Debt securities issued by United States Treasury	71,564		(66		)	506,449		—			578,013		(66		)
Asset-backed securities	224,100		(27		)	213,651		(173		)	437,751		(200		)
Mortgage-backed securities issued by United States government-sponsored enterprises	—		—			277,684		(717		)	277,684		(717		)
Foreign government bonds	33,606		—			51,772		(16		)	85,378		(16		)
Total	$	1,306,824	$	(184	)	$	2,615,187	$	(1,388	)	$	3,922,011	$	(1,572	)

The gross unrealized losses related to fixed income securities were due to changes in interest rates. We have determined that the gross unrealized losses on investment securities at October 26, 2014 are temporary in nature. Currently, we have the intent and ability to hold our investments with impairment indicators until maturity.

The amortized cost and estimated fair value of cash equivalents and marketable securities, which are primarily debt instruments, are classified as available-for-sale at October 26, 2014 and January 26, 2014 and are shown below by contractual maturity.



	October 26, 2014				January 26, 2014
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
	(In thousands)
Less than 1 year	$	1,378,709	$	1,379,705	$	1,883,132	$	1,883,753
Due in 1 - 5 years	2,490,537		2,497,644		2,114,289		2,117,387
Mortgage-backed securities issued by government-sponsored enterprises not due at a single maturity date	115,238		117,543		90,472		91,508
Total	$	3,984,484	$	3,994,892	$	4,087,893	$	4,092,648

Net realized gains and losses for the three and nine months ended October 26, 2014, and for the three months ended October 27, 2013, were not significant. Net realized gains for the nine months ended October 27, 2013 were $1.8 million.