Investment Securities

Securities designated as available-for-sale are carried at fair value. However, the unrealized difference between amortized cost and fair value of securities available-for-sale is excluded from net income unless there is an other than temporary impairment and it is reported, net of deferred taxes, as a component of shareholders' equity as accumulated other comprehensive income (loss). Securities designated as held-to-maturity are carried at amortized cost, as the Company has the ability, and management has the positive intent, to hold these securities to maturity. Premiums and discounts on securities are amortized and accreted according to the interest method.

Our primary objective in managing the investment portfolio is to maintain a portfolio of high quality, highly liquid investments yielding competitive returns. We are required under federal regulations to maintain adequate liquidity to ensure safe and sound operations. We maintain investment balances based on a continuing assessment of cash flows, the level of loan production, current interest rate risk strategies and an assessment of the potential future direction of market interest rate changes. Investment securities differ in terms of default, interest rate, liquidity and expected rate of return risks.

The following table summarizes the amortized cost and estimated fair value of investment securities and presents the related gross unrealized gains and losses:



March 31, 2016
(dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Available-for-Sale:
Residential mortgage-backed securities-GSE	$	278,521	$	920	$	2,379	$	277,062
Residential mortgage-backed securities-Private	31,079		399		44		31,434
Commercial mortgage-backed securities-GSE	21,880		242		—		22,122
Commercial mortgage-backed securities-Private	17,858		140		150		17,848
Corporate notes	37,524		21		17		37,528
Total available-for-sale	386,862		1,722		2,590		385,994
Held-to-Maturity:
Residential mortgage-backed securities-GSE	118,194		698		109		118,783
Residential mortgage-backed securities-Private	16,877		—		32		16,845
Commercial mortgage-backed securities-Private	10,056		169		—		10,225
Total held-to-maturity	145,127		867		141		145,853
Total investment securities	$	531,989	$	2,589	$	2,731	$	531,847

December 31, 2015
(dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Available-for-Sale:
Obligations of U.S. government sponsored enterprises	$	2,005	$	3	$	—	$	2,008
Residential mortgage-backed securities-GSE	286,057		339		8,289		278,107
Residential mortgage-backed securities-Private	33,235		578		236		33,577
Commercial mortgage-backed securities-GSE	21,980		—		368		21,612
Commercial mortgage-backed securities-Private	17,869		—		294		17,575
Corporate notes	37,669		—		114		37,555
Total available-for-sale	398,815		920		9,301		390,434
Held-to-Maturity:
Residential mortgage-backed securities-GSE	120,197		—		2,310		117,887
Residential mortgage-backed securities-Private	17,712		—		298		17,414
Commercial mortgage-backed securities-Private	10,058		—		174		9,884
Total held-to-maturity	147,967		—		2,782		145,185
Total investment securities	$	546,782	$	920	$	12,083	$	535,619

As a member of the Federal Home Loan Bank of Atlanta (“FHLB”), the Bank is required to own capital stock in the FHLB based generally upon the balances of total assets and FHLB advances. FHLB capital stock is pledged to secure FHLB advances. This investment is carried at cost since no ready market exists for FHLB stock and there is no quoted market value. However, redemption of this stock has historically been at par value. The Bank owned a total of $4.9 million of FHLB stock at March 31, 2016 and $6.0 million at December 31, 2015. Due to the redemption provisions of FHLB stock, we have estimated that fair value approximated cost and that this investment was not impaired at March 31, 2016. FHLB stock is included in other assets at its original cost basis.

As a member bank of the Federal Reserve Bank of Richmond (“FRBR”), the Bank also is required to own capital stock of the FRBR based upon a percentage of the Bank's common stock and surplus. This investment is carried at cost since no ready market exists for FRBR stock and there is no quoted market value. At March 31, 2016 and December 31, 2015, the Bank owned a total of $9.8 million and $9.9 million of FRBR stock, respectively. Because this investment is in an entity of the U.S. government, we have estimated that fair value approximated the cost and that this investment was not impaired at March 31, 2016. FRBR stock is included in other assets at its original cost basis.

At March 31, 2016, $161.4 million of the investment securities portfolio was pledged to secure public deposits, $16.9 million was pledged to retail repurchase agreements and $156.3 million was pledged to others, leaving $196.5 million available as pledgeable collateral.

The Bank did not sell any investment securities during the three months ended March 31, 2016 or the three months ended March 31, 2015.

The following tables show our investments' estimated fair value and gross unrealized losses, aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position, at March 31, 2016 and December 31, 2015. The change in unrealized losses during the three months ending March 31, 2016 was attributed to changes in interest rates and not to changes in the credit quality of these securities. All unrealized losses on investment securities are considered by management to be temporary given the credit quality of these investment securities or the short duration of the unrealized loss, or both.



	Less than 12 Months				12 Months or More				Total
(dollars in thousands)	Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses
March 31, 2016
Available-for-Sale:
Residential mortgage-backed securities-GSE	$	—	$	—	$	189,610	$	2,379	$	189,610	$	2,379
Residential mortgage-backed securities-Private	2,970		32		621		12		3,591		44
Commercial mortgage-backed securities-GSE	—		—		—		—		—		—
Commercial mortgage-backed securities-Private	7,399		150		—		—		7,399		150
Corporate Notes	10,224		4		9,994		13		20,218		17
Total available-for-sale	20,593		186		200,225		2,404		220,818		2,590
Held-to-Maturity:
Residential mortgage-backed securities-GSE	—		—		13,628		109		13,628		109
Residential mortgage-backed securities-Private	16,845		32		—		—		16,845		32
Total held-to-maturity	16,845		32		13,628		109		30,473		141
Total	$	37,438	$	218	$	213,853	$	2,513	$	251,291	$	2,731

December 31, 2015
Available-for-Sale
Residential mortgage-backed securities-GSE	$	137,998	$	2,560	$	132,148	$	5,729	$	270,146	$	8,289
Residential mortgage-backed securities-Private	26,265		231		636		5		26,901		236
Commercial mortgage-backed securities-GSE	21,612		368		—		—		21,612		368
Commercial mortgage-backed securities-Private	17,575		294		—		—		17,575		294
Corporate notes	30,523		114		—		—		30,523		114
Total available-for-sale	233,973		3,567		132,784		5,734		366,757		9,301
Held-to-Maturity:
Residential mortgage-backed securities-GSE	83,014		1,481		34,872		829		117,886		2,310
Residential mortgage-backed securities-Private	17,414		298		—		—		17,414		298
Commercial mortgage-backed securities-Private	9,884		174		—		—		9,884		174
Total held-to-maturity	110,312		1,953		34,872		829		145,184		2,782
Total	$	344,285	$	5,520	$	167,656	$	6,563	$	511,941	$	12,083

At March 31, 2016 and December 31, 2015, there were 28 and 18 securities that were in a continuous unrealized loss position for 12 months or more, respectively.

We analyzed our securities portfolio at March 31, 2016, and considered ratings, fair value, cash flows and other factors to determine if any of the securities were other than temporarily impaired. Since none of the unrealized losses relate to the marketability of the securities or the issuer’s ability to honor redemption obligations, and we have determined that it is not more likely than not that we will be required to sell the security before recovery of its amortized cost basis, none of the securities are deemed to be other than temporarily impaired.

The aggregate amortized cost and fair value of securities at March 31, 2016, by remaining contractual maturity, are shown in the following table. Actual expected maturities may differ from contractual maturities because issuers may have the right to call or prepay the obligations. Mortgage backed securities are grouped based on stated maturity date, but actual maturity will vary based on the actual repayment of the underlying mortgage loans.



	Available-for-Sale				Held-to-Maturity
(dollars in thousands)	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
U.S. government sponsored agencies
Due in one year or less	$	—	$	—	$	—	$	—
Residential mortgage-backed securities-GSE
Due after five years through 10 years	1,670		1,716		—		—
Due after ten years	276,851		275,346		118,194		118,783
Residential mortgage-backed securities-Private
Due after ten years	31,079		31,434		16,877		16,845
Commercial mortgage-backed securities-GSE
Due after one year through five years	21,880		22,122		—		—
Commercial mortgage-backed securities-Private
Due after ten years	17,858		17,848		10,056		10,225
Corporate notes
Due in one year or less	20,465		20,461		—		—
Due after one year through five years	17,059		17,067		—		—
Total	$	386,862	$	385,994	$	145,127	$	145,853