4. Investment in Available-for-Sale Securities

The following is a summary of the Company’s investments in available-for-sale securities as of March 31, 2014 (unaudited):

	Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. federal agency securities	$	90,322	$	103	$	(258)	$	90,167
Municipal securities		660,444		2,107		-		662,551
Certificates of deposit		1,692,480		16,155		(19,456)		1,689,179
Corporate debt securities		72,677		379		(3,163)		69,893
	$	2,515,923	$	18,744	$	(22,877)	$	2,511,790

The following is a summary of the Company’s investments in available-for-sale securities as of December 31, 2013:

	Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. federal agency securities	$	90,549	$	93	$	(277)	$	90,365
Municipal securities		735,826		2,175		(6)		737,995
Certificates of deposit		1,539,377		12,281		(19,398)		1,532,260
Corporate debt securities		174,738		275		(9,091)		165,922
	$	2,540,490	$	14,824	$	(28,772)	$	2,526,542

The Company’s investment portfolio had a net realized losses of $8,103 and $10,986 for the three months ended March 31, 2014 and 2013, respectively.

The cost and fair value of investments in fixed income available-for-sale debt securities, by contractual maturity, as of March 31, 2014 (unaudited), are as follows:

	Cost		Fair Value
Due within one year	$	1,058,930	$	1,051,561
Due after one year through three years		748,657		757,623
Due after three years		708,336		702,606
	$	2,515,923	$	2,511,790

Expected maturities will differ from contractual maturities because the issuers of certain debt securities have the right to call or prepay their obligations without any penalties. The Company has classified the entire fair value of its investment in available-for-sale debt securities as current assets in the accompanying balance sheets.