Marketable Securities

All of the cash equivalents and marketable securities are classified as “available-for-sale” securities. Investments in both fixed and floating rate interest earning instruments carry a degree of interest rate risk. Fixed rate debt securities may have their market value adversely impacted due to a rise in interest rates, while floating rate securities may produce less income than expected if interest rates fall. Due in part to these factors, our future investment income may fall short of expectations due to changes in interest rates or if the decline in fair value of our publicly traded debt or equity investments is judged to be other-than-temporary. We may suffer losses in principal if we are forced to sell securities that decline in market value due to changes in interest rates. However, because any debt securities we hold are classified as “available-for-sale,” no gains or losses are realized in our statement of income due to changes in interest rates unless such securities are sold prior to maturity or unless declines in market values are determined to be other-than-temporary. 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.

The following is a summary of cash equivalents and marketable securities at January 27, 2013 and January 29, 2012:



	January 27, 2013
	Amortized Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value
	(In thousands)
Debt securities of United States government agencies	$	867,087	$	1,199	$	(139	)	$	868,147
Corporate debt securities	1,255,297		3,175		(542		)	1,257,930
Mortgage backed securities issued by United States government-sponsored enterprises	183,034		6,194		(57		)	189,171
Money market funds	195,790		—		—			195,790
Debt securities issued by United States Treasury	785,228		1,102		(105		)	786,225
Total	$	3,286,436	$	11,670	$	(843	)	$	3,297,263
Classified as:
Cash equivalents								$	302,166
Marketable securities								2,995,097
Total								$	3,297,263



	January 29, 2012
	Amortized Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value
	(In thousands)
Debt securities of United States government agencies	$	769,300	$	1,605	$	(151	)	$	770,754
Corporate debt securities	1,114,439		3,268		(260		)	1,117,447
Mortgage backed securities issued by United States government-sponsored enterprises	156,668		4,964		(73		)	161,559
Money market funds	290,732		—		—			290,732
Debt securities issued by United States Treasury	533,616		2,161		(3		)	535,774
Total	$	2,864,755	$	11,998	$	(487	)	$	2,876,266
Classified as:
Cash equivalents								$	414,566
Marketable securities								2,461,700
Total								$	2,876,266

The following table provides the breakdown of the investments with unrealized losses at January 27, 2013:



	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	$	563,842	$	(35	)	$	694,088	$	(507	)	$	1,257,930	$	(542	)
Mortgage backed securities issued by United States government-sponsored enterprises	5,912		—			183,259		(57		)	189,171		(57		)
Debt securities of United States Treasury	278,383		(15		)	507,842		(90		)	786,225		(105		)
Debt securities issued by United States government agencies	355,378		(23		)	512,769		(116		)	868,147		(139		)
Total	$	1,203,515	$	(73	)	$	1,897,958	$	(770	)	$	3,101,473	$	(843	)

We performed an impairment review of our investment portfolio as of January 27, 2013. Factors considered included general market conditions, the duration and extent to which fair value is below cost, and our intent and ability to hold an investment for a sufficient period of time to allow for recovery in value. We also consider specific adverse conditions related to the financial health of and business outlook for an investee, including industry and sector performance, changes in technology, operational and financing cash flow factors, and changes in an investee’s credit rating. Investments that we identify as having an indicator of impairment are subject to further analysis to determine if the investment was other than temporarily impaired. Based on our quarterly impairment review and having considered the guidance in the relevant accounting literature, we did not record any other-than-temporary impairment charges during fiscal year 2013. We concluded that our investments were appropriately valued and that no other than temporary impairment charges were necessary on our portfolio of available for sale investments as of January 27, 2013.

As of January 27, 2013, we had 9 investments that were in an unrealized loss position with total unrealized losses amounting to $0.1 million and with a duration of less than one year. 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 January 27, 2013 are temporary in nature. Currently, we have the intent and ability to hold our investments with impairment indicators until maturity.

Net realized gains were $0.5 million, $0.4 million and $1.5 million for fiscal years 2013, 2012, and 2011, respectively. As of January 27, 2013, we had a net unrealized gain of $10.9 million, which was comprised of gross unrealized gains of $11.7 million, offset by $0.8 million of gross unrealized losses. As of January 29, 2012, we had a net unrealized gain of $11.5 million, which was comprised of gross unrealized gains of $12.0 million, offset by $0.5 million of gross unrealized losses.

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 January 27, 2013 and January 29, 2012 and are shown below by contractual maturity.



	January 27, 2013				January 29, 2012
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
	(In thousands)
Less than one year	$	1,397,350	$	1,399,304	$	1,705,916	$	1,708,154
Due in 1 - 5 years	1,777,785		1,783,103		1,047,956		1,053,265
Mortgage-backed securities issued by government-sponsored enterprises not due at a single maturity date	111,301		114,856		110,883		114,847
Total	$	3,286,436	$	3,297,263	$	2,864,755	$	2,876,266