3.INVESTMENTS

The following table summarizes the Company’s investments at:

December 31, 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	$	3,978	$	-	$	-	$	3,978	$	-	$	-
Municipal securities	709,207		63		192		709,078		192		-
U.S. government agency securities	23,369		-		58		23,311		58		-
U.S. Treasuries	8,056		-		13		8,043		13		-
Long-term:
Municipal securities	11,071		-		8		11,063		8		-
U.S. government agency securities	4,277		-		25		4,252		25		-

Total	$	759,958	$	63	$	296	$	759,725	$	296	$	-


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 years ended December 31, 2015 and 2014, realized gains or losses recognized on the sale of investments were not significant. During the year ended December 31, 2013, the Company recognized $2.5 million of realized gains on the sale of available-for-sale investments. Realized gains or losses on the sale of all other investments during the year ended December 31, 2013 were not significant.

The Company recognized a net gain through earnings on its trading securities as follows for the years ended:

	2015		2014		2013
Gain (loss) on transfer from available-for-sale to trading	$	-	$	-	$	-
Gain on trading securities sold	250		978		255
(Loss) gain on trading securities held	-		(177)		816

Gain on trading securites	$	250	$	801	$	1,071

The Company’s investments at December 31, 2015 and 2014 in commercial paper, municipal securities, U.S. government agency securities, U.S. treasuries 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 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:

	December 31, 2015				December 31, 2014

	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Less than 1 year:
Commercial paper	$	3,978	$	3,978	$	19,482	$	19,480
Municipal securities	709,207		709,078		744,542		744,647
U.S. government agency securities	23,369		23,311		9,199		9,198
U.S. Treasuries	8,056		8,043		-		-
Due 1 -10 years:
Municipal securities	11,071		11,063		42,940		42,950
U.S. government agency securities	4,277		4,252		-		-
Due 11 - 20 years:
Auction rate securities	-		-		3,910		3,910
Due 21 - 30 years:
Variable rate demand notes	-		-		4,001		4,001

Total	$	759,958	$	759,725	$	824,074	$	824,186