4.INVESTMENTS

The following table summarizes the Company’s investments at:

September 30, 2015	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Fair Value		Continuous Unrealized Loss Position less than 12 Months		Continuous Unrealized Loss Position greater than 12 Months
Held-to-Maturity
Short-term:
Commercial paper	$	306,858	$	-	$	-	$	306,858	$	-	$	-
U.S. Treasuries	92,994		5		-		92,999		-		-
Certificates of deposit	44,506		-		-		44,506		-		-
Municipal securities	611,370		319		10		611,679		10		-
U.S. government agency securities	487,495		23		4		487,514		4		-
Long-term:
Municipal securities	29,333		16		4		29,345		4		-
U.S. government agency securities	5,022		-		3		5,019		3		-

Total	$	1,577,578	$	363	$	21	1,577,920		$	21	$	-

Trading
Short-term:
Auction rate securities							1,487
Long-term:
Auction rate securities							-

Total							$	1,579,407


December 31, 2014	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Fair Value		Continuous Unrealized Loss Position less than 12 Months		Continuous Unrealized Loss Position greater than 12 Months

Held-to-Maturity
Short-term:
Commercial paper	$	19,482	$	-	$	2	$	19,480	$	-	$	-
Municipal securities	744,542		105		-		744,647		-		-
U.S. government agency securities	9,199		-		1		9,198		-		-
Long-term:
Municipal securities	42,940		10		-		42,950		-		-
Available-for-sale
Variable rate demand notes	4,001		-		-		4,001		-		-

Total	$	820,164	$	115	$	3	820,276		$	-	$	-

Trading
Short-term:
Auction rate securities							3,910
Long-term:
Auction rate securities							-

Total							$	824,186

During the three- and nine-months ended September 30, 2015 and September 30, 2014, realized gains or losses recognized on the sale of investments were not significant. During the three- and nine-months ended September 30, 2015 and September 30, 2014, the net gains recognized on the Company’s trading securities were not significant.

The Company’s investments at September 30, 2015 and December 31, 2014 in commercial paper, U.S. Treasuries, certificates of deposit, municipal securities, U.S. government agency securities and/or variable rate demand notes (“VRDNs”) carried investment grade credit ratings. VRDNs are floating rate municipal bonds with embedded put options that allow the bondholder to sell the security at par plus accrued interest. All of the put options are secured by a pledged liquidity source. While they are classified as marketable investment securities, the put option allows the VRDNs to be liquidated at par on a same day, or more generally on a seven day, settlement basis. All of the Company’s investments at September 30, 2015 and December 31, 2014 in municipal, educational or other public body securities with an auction reset feature (“auction rate securities”) also carried investment grade credit ratings.

The following table summarizes the underlying contractual maturities of the Company’s investments at:

	September 30, 2015				December 31, 2014

	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Less than 1 year:
Commercial paper	$	306,858	$	306,858	$	19,482	$	19,480
U.S. Treasuries	92,994		92,999		-		-
Certificates of deposit	44,506		44,506		-		-
Municipal securities	611,370		611,679		744,542		744,647
U.S. government agency securities	487,495		487,514		9,199		9,198
Due 1 - 10 years:
Municipal securities	29,333		29,345		42,940		42,950
U.S. government agency securities	5,022		5,019		-		-
Due 11 - 20 years:
Auction rate securities	1,487		1,487		3,910		3,910
Due 21 - 30 years:
Variable rate demand notes	-		-		4,001		4,001

Total	$	1,579,065	$	1,579,407	$	824,074	$	824,186