INVESTMENTS

The following table presents the amortized cost, gross unrealized gains and losses and fair value of securities available for sale:



	December 31, 2013
(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Available for sale securities:
Obligations of U.S. Government-sponsored enterprises	$	93,218	$	700	$	(388	)	$	93,530
Obligations of states and political subdivisions	49,721		983		(1,761		)	48,943
Agency mortgage-backed securities	298,623		2,675		(9,184		)	292,114
	$	441,562	$	4,358	$	(11,333	)	$	434,587

	December 31, 2012
(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Available for sale securities:
Obligations of U.S. Government-sponsored enterprises	$	149,039	$	3,329	$	—		$	152,368
Obligations of states and political subdivisions	51,202		2,279		(478		)	53,003
Agency mortgage-backed securities	427,221		7,884		(264		)	434,841
	$	627,462	$	13,492	$	(742	)	$	640,212

At December 31, 2013, and December 31, 2012, there were no holdings of securities of any one issuer in an amount greater than 10% of shareholders’ equity, other than the U.S. Government agencies and sponsored enterprises. The agency mortgage-backed securities are all issued by U.S. Government-sponsored enterprises. Available for sale securities having a fair value of $270.1 million and $359.3 million at December 31, 2013, and December 31, 2012, respectively, were pledged as collateral to secure deposits of public institutions and for other purposes as required by law or contract provisions.

The amortized cost and estimated fair value of debt securities classified as available for sale at December 31, 2013, by contractual maturity, are shown below. Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. The weighted average life of the mortgage-backed securities is approximately 5 years.



(in thousands)	Amortized Cost		Estimated Fair Value
Due in one year or less	$	887	$	893
Due after one year through five years	107,842		108,582
Due after five years through ten years	20,512		20,387
Due after ten years	13,698		12,611
Mortgage-backed securities	298,623		292,114
	$	441,562	$	434,587

The following table represents a summary of available for sale investment securities that had an unrealized loss:



	December 31, 2013
	Less than 12 months				12 months or more				Total
(in thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Obligations of U.S. Government-sponsored enterprises	$	30,221	$	388	$	—	$	—	$	30,221	$	388
Obligations of states and political subdivisions	17,141		952		7,168		809		24,309		1,761
Agency mortgage-backed securities	159,999		7,338		21,437		1,846		181,436		9,184
	$	207,361	$	8,678	$	28,605	$	2,655	$	235,966	$	11,333

	December 31, 2012
	Less than 12 months				12 months or more				Total
(in thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Obligations of states and political subdivisions	$	6,434	$	122	$	3,389	$	356	$	9,823	$	478
Agency mortgage-backed securities	40,471		143		11,266		121		51,737		264
	$	46,905	$	265	$	14,655	$	477	$	61,560	$	742

The unrealized losses at both December 31, 2013, and December 31, 2012, were primarily attributable to changes in market interest rates since the securities were purchased. Management systematically evaluates investment securities for other-than-temporary declines in fair value on a quarterly basis. This analysis requires management to consider various factors, which include among other considerations (1) the present value of the cash flows expected to be collected compared to the amortized cost of the security, (2) duration and magnitude of the decline in value, (3) the financial condition of the issuer or issuers, (4) structure of the security, and (5) the intent to sell the security or whether it is more likely than not that the Company would be required to sell the security before its anticipated recovery in market value. At December 31, 2013, management performed its quarterly analysis of all securities with an unrealized loss and concluded no individual securities were other-than-temporarily impaired.

The gross gains and gross losses realized from sales of available for sale investment securities were as follows:



	December 31,
(in thousands)	2013			2012			2011
Gross gains realized	$	1,477		$	1,399		$	1,450
Gross losses realized	(182		)	(243		)	—
Proceeds from sales	159,604			110,876			84,456

Other Investments, At Cost

As a member of the FHLB system administered by the Federal Housing Finance Board, the Bank is required to maintain a minimum investment in capital stock with the FHLB Des Moines consisting of membership stock and activity-based stock. The FHLB capital stock of $6.0 million is recorded at cost, which represents redemption value, and is included in other investments in the consolidated balance sheets. The Bank also has a $0.7 million investment in the FHLB of San Francisco. The remaining amounts in Other investments include the Company's investment in unconsolidated trusts used to issue preferred securities to third parties (see Note 12 - Subordinated Debentures) and various private equity investments.