Investments

Short-term investments consist of high grade municipal and corporate bonds and other debt securities. The Company classifies its marketable securities as available-for-sale based upon management’s determination that the underlying cash invested in these securities is available for operations as necessary.

The following tables provide a summary of marketable investments by type (in thousands):



	December 30, 2012
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Municipal bonds	$	236,819	$	1,442	$	(311	)	$	237,950
Corporate bonds	158,563		2,467		(49		)	160,981
Certificates of deposit	225,000		—		—			225,000
U.S. agency securities	71,620		440		—			72,060
Non-U.S. government securities	10,172		32		—			10,204
Total	$	702,174	$	4,381	$	(360	)	$	706,195

	June 24, 2012
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Municipal bonds	$	209,626	$	2,036	$	(58	)	$	211,604
Corporate bonds	144,942		1,848		(123		)	146,667
Certificates of deposit	130,000		—		—			130,000
U.S. agency securities	68,156		450		(7		)	68,599
Non-U.S. government securities	8,746		15		(3		)	8,758
Total	$	561,470	$	4,349	$	(191	)	$	565,628

The following tables present the gross unrealized losses and estimated fair value of the Company's investment securities, aggregated by investment type and length of time that individual investments securities have been in a continuous unrealized loss position (in thousands):



	December 30, 2012
	Less than 12 Months					Greater than 12 Months				Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Municipal bonds	$	77,718	$	(311	)	$	—	$	—	$	77,718	$	(311	)
Corporate bonds	21,128		(49		)	—		—		21,128		(49		)
Total	$	98,846	$	(360	)	$	—	$	—	$	98,846	$	(360	)
Number of securities with an unrealized loss			56					—				56

	June 24, 2012
	Less than 12 Months					Greater than 12 Months				Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Municipal bonds	$	30,102	$	(58	)	$	—	$	—	$	30,102	$	(58	)
Corporate bonds	30,550		(123		)	—		—		30,550		(123		)
U.S. agency securities	3,014		(7		)	—		—		3,014		(7		)
Non-U.S. government securities	1,543		(3		)	—		—		1,543		(3		)
Total	$	65,209	$	(191	)	$	—	$	—	$	65,209	$	(191	)
Number of securities with an unrealized loss			33					—				33

The contractual maturities of marketable investments at December 30, 2012 were as follows (in thousands):



	December 30, 2012
	Within One Year		After One, Within Five Years		After Five, Within Ten Years		After Ten Years		Total
Municipal bonds	$	63,142	$	174,808	$	—	$	—	$	237,950
Corporate bonds	34,905		126,076		—		—		160,981
Certificates of deposit	225,000		—		—		—		225,000
U.S. agency securities	29,187		42,873		—		—		72,060
Non-U.S. government securities	2,523		7,681		—		—		10,204
Total	$	354,757	$	351,438	$	—	$	—	$	706,195