Investments

The amortized cost and fair value of securities available for sale are as follows:



	June 30, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Available for sale:
Mortgage-backed securities	$	167,203	$	119	$	(6,906	)	$	160,416
Utah Housing Corporation bonds	18,546		—		(817		)	17,729
Total	$	185,749	$	119	$	(7,723	)	$	178,145

	December 31, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Available for sale:
Mortgage-backed securities	$	227,607	$	650	$	(3,210	)	$	225,047
Utah Housing Corporation bonds	20,000		—		(959		)	19,041
Total	$	247,607	$	650	$	(4,169	)	$	244,088

The following table summarizes the amount of gross unrealized losses for our mortgage-backed securities and Utah Housing Corporation bonds and the estimated fair value for securities having gross unrealized losses, categorized by length of time the securities have been in an unrealized loss position:



	Less than 12 months					12 months or more					Total
	Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value
As of June 30, 2018:
Mortgage-backed securities	$	(1,568	)	$	49,747	$	(5,338	)	$	107,182	$	(6,906	)	$	156,929
Utah Housing Corporation bonds	—			—		(817		)	17,729		(817		)	17,729
Total	$	(1,568	)	$	49,747	$	(6,155	)	$	124,911	$	(7,723	)	$	174,658

As of December 31, 2017:
Mortgage-backed securities	$	(772	)	$	77,356	$	(2,438	)	$	110,500	$	(3,210	)	$	187,856
Utah Housing Corporation bonds	(77		)	4,923		(882		)	14,118		(959		)	19,041
Total	$	(849	)	$	82,279	$	(3,320	)	$	124,618	$	(4,169	)	$	206,897

Our investment portfolio is comprised primarily of mortgage-backed securities issued by Ginnie Mae, Fannie Mae and Freddie Mac, with amortized costs of $72 million, $49 million, and $46 million, respectively, at June 30, 2018. We own these securities to meet our requirements under the Community Reinvestment Act. In the second quarter of 2018, we elected to sell nine securities totaling $41 million to better align the portfolio with the Community Reinvestment Act requirements, and we recognized a $2 million loss upon the sale of those securities. As of June 30, 2018, 75 of the 84 separate mortgage-backed securities in our investment portfolio had unrealized losses, and 35 of the 75 securities in a net loss position were issued under Ginnie Mae programs that carry a full faith and credit guarantee from the U.S. Government. The remaining securities in a net loss position carry a principal and interest guarantee by Fannie Mae or Freddie Mac, respectively. We have the ability and the intent to hold these securities for a period of time sufficient for the market price to recover to at least the adjusted amortized cost of the security. As of December 31, 2017, 62 of the 92 separate mortgage-backed securities in our investment portfolio had unrealized losses, and 31 of the 62 securities in a net loss position were issued under Ginnie Mae programs that carry a full faith and credit guarantee from the U.S. Government. The remainder carried a principal and interest guarantee by Fannie Mae or Freddie Mac, respectively.

We also invest in Utah Housing Corporation bonds for the purpose of complying with the Community Reinvestment Act. These bonds are Aa3 rated by Moody’s Investors Service. The amortized cost of the investment on the consolidated balance sheet at June 30, 2018 and December 31, 2017 was $19 million and $20 million, respectively. We have the intent and ability to hold these bonds for a period of time sufficient for the market price to recover to at least the adjusted amortized cost of the security.

As of June 30, 2018, the amortized cost and fair value of securities, by contractual maturities, are summarized below. Contractual maturities versus actual maturities may differ due to the effect of prepayments.



Year of Maturity	Amortized Cost		Estimated Fair Value
2038	$	269	$	284
2039	3,099		3,203
2042	10,099		9,381
2043	15,371		14,823
2044	24,183		23,464
2045	28,117		26,883
2046	41,807		39,789
2047	59,890		57,416
2048	2,914		2,902
Total	$	185,749	$	178,145

The mortgage-backed securities have been pledged to the Federal Reserve Bank (the “FRB”) as collateral against any advances and accrued interest under the Primary Credit lending program sponsored by the FRB. We had $161 million and $218 million par value of mortgage-backed securities pledged to this borrowing facility at June 30, 2018 and December 31, 2017, respectively, as discussed further in Note 6, “Borrowings.”