4. Investment securities:

The amortized cost and fair value of investment securities aggregated by investment category at September 30, 2017 and December 31, 2016 are summarized as follows:


			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
September 30, 2017	Cost		Gains		Losses		Value
Available-for-sale:
U.S. Treasury securities	$	20,045	$	29	$	28	$	20,046
U.S. Government-sponsored enterprises		85,482		83		915		84,650
State and municipals:
Taxable		14,594		615		2		15,207
Tax-exempt		98,494		2,062		51		100,505
Residential Mortgage-backed securities:
U.S. Government agencies		16,045		21		33		16,033
U.S. Government-sponsored enterprises		16,492		29		95		16,426
Commercial Mortgage-backed securities:
U.S. Government-sponsored enterprises		6,326				85		6,241
Common equity securities		30						30
Total	$	257,508	$	2,839	$	1,209	$	259,138
Held-to-maturity:
Tax-exempt state and municipals	$	6,859	$	185	$	2	$	7,042
Residential Mortgage-backed securities:
U.S. Government agencies		58						58
U.S. Government-sponsored enterprises		2,647		165				2,812
Total	$	9,564	$	350	$	2	$	9,912


			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
December 31, 2016	Cost		Gains		Losses		Value
Available-for-sale:
U.S. Treasury securities	$	7,570			$	132	$	7,438
U.S. Government-sponsored enterprises		82,314	$	79		1,480		80,913
State and municipals:
Taxable		14,698		566		39		15,225
Tax-exempt		110,931		2,309		640		112,600
Residential Mortgage-backed securities:
U.S. Government agencies		21,041		48		47		21,042
U.S. Government-sponsored enterprises		22,303		48		159		22,192
Total	$	258,857	$	3,050	$	2,497	$	259,410
Held-to-maturity:
Tax-exempt state and municipals	$	6,862	$	72	$	67	$	6,867
Residential Mortgage-backed securities:
U.S. Government agencies		68		1				69
U.S. Government-sponsored enterprises		3,587		191				3,778
Total	$	10,517	$	264	$	67	$	10,714

The maturity distribution of the fair value, which is the net carrying amount, of the debt securities classified as available-for-sale at September 30, 2017, is summarized as follows:


	Fair
September 30, 2017	Value
Within one year	$	15,858
After one but within five years		148,810
After five but within ten years		40,582
After ten years		15,158
		220,408
Mortgage-backed securities		38,700
Total	$	259,108

The maturity distribution of the amortized cost and fair value, of debt securities classified as held-to-maturity at September 30, 2017, is summarized as follows:


	Amortized		Fair
September 30, 2017	Cost		Value
Within one year
After one but within five years
After five but within ten years
After ten years	$	6,859	$	7,042
		6,859		7,042
Mortgage-backed securities		2,705		2,870
Total	$	9,564	$	9,912

Securities with a carrying value of $165,205 and $144,750 at September 30, 2017 and December 31, 2016, respectively, were pledged to secure public deposits and certain other deposits as required or permitted by law.

Securities and short-term investment activities are conducted with a diverse group of government entities, corporations and state and local municipalities. The counterparty’s creditworthiness and type of collateral is evaluated on a case-by-case basis. At September 30, 2017 and December 31, 2016, there were no significant concentrations of credit risk from any one issuer, with the exception of U.S. Government agencies and sponsored enterprises that exceeded 10.0 percent of stockholders’ equity.

The fair value and gross unrealized losses of investment securities with unrealized losses for which an other-than-temporary impairment (“OTTI”) has not been recognized at September 30, 2017 and December 31, 2016, aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position, are summarized as follows:


	Less Than 12 Months				12 Months or More				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
September 30, 2017	Value		Losses		Value		Losses		Value		Losses
U.S. Treasury securities	$	5,494	$	28					$	5,494	$	28
U.S. Government-sponsored enterprises		48,573		376	$	29,309	$	539		77,882		915
State and municipals:
Taxable		551		2						551		2
Tax-exempt		5,330		50		2,482		3		7,812		53
Residential Mortgage-backed securities:
U.S. Government agencies		5,671		13		3,175		20		8,846		33
U.S. Government-sponsored enterprises		8,492		25		4,775		70		13,267		95
Commercial Mortgage-backed securities:
U.S. Government-sponsored enterprises		6,241		85						6,241		85
Total	$	80,352	$	579	$	39,741	$	632	$	120,093	$	1,211


	Less Than 12 Months				12 Months or More				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
December 31, 2016	Value		Losses		Value		Losses		Value		Losses
U.S. Treasury securities	$	7,438	$	132					$	7,438	$	132
U.S. Government-sponsored enterprises		59,460		1,480						59,460		1,480
State and municipals:
Taxable		1,035		39						1,035		39
Tax-exempt		55,166		707	$	226				55,392		707
Residential Mortgage-backed securities:
U.S. Government agencies		5,917		27		1,496	$	20		7,413		47
U.S. Government-sponsored enterprises		16,412		85		2,712		74		19,124		159
Total	$	145,428	$	2,470	$	4,434	$	94	$	149,862	$	2,564

The Company had 74 investment securities, consisting of 11 tax-exempt state and municipal obligations, 2 U.S. Treasury securities, one taxable municipal obligation, 29 U.S. Government-sponsored enterprise securities, and 31 mortgage-backed securities that were in unrealized loss positions at September 30, 2017. Of these securities, 4 tax-exempt state and municipal obligations, 14 mortgage-backed securities and 10 U.S. Government-sponsored enterprise securities were in a continuous unrealized loss position for twelve months or more. Management does not consider the unrealized losses on the debt securities, as a result of changes in interest rates, to be OTTI based on historical evidence that indicates the cost of these securities is recoverable within a reasonable period of time in relation to normal cyclical changes in the market rates of interest. Moreover, because there has been no material change in the credit quality of the issuers or other events or circumstances that may cause a significant adverse impact on the fair value of these securities, and management does not intend to sell these securities and it is unlikely that the Company will be required to sell these securities before recovery of their amortized cost basis, which may be maturity, the Company does not consider the unrealized losses to be OTTI at September 30, 2017. There was no OTTI recognized for the three or nine months ended September 30, 2017 and 2016.

The Company had 163 investment securities, consisting of 107 tax-exempt state and municipal obligations, 2 taxable state and municipal obligations, 2 U.S. Treasury securities, 22 U.S. Government-sponsored enterprise securities and 30 mortgage-backed securities that were in unrealized loss positions at December 31, 2016. Of these securities, 9 mortgage-backed securities, and 2 tax-exempt state and municipal securities were in a continuous unrealized loss position for twelve months or more.