Included in total investment securities

held-to-maturity

are securities pledged to secure public deposits and repurchase agreements at fair value amounting to $2,298,053,000

nd $1,866,989,000 at September 30, 2021 and December 31, 2020, respectively. Also included are securities pledged for borrowing at the FHLBB at fair value amounting to $691,058,000 and $537,367,000 at September 30, 2021 and December 31, 2020, respectively. There were no sales of

held-to-maturity

securities for the nine months ended September 30, 2021 or September 30, 2020, respectively.

At September 30, 2021 and December 31, 2020, all mortgage-backed securities are obligations of U.S. Government Sponsored Enterprises. Debt securities of U.S. Government Sponsored Enterprises and U.S. Government Sponsored Enterprises Mortgage-Backed Securities primarily refer to debt securities of Fannie Mae and Freddie Mac.

The following table shows the maturity distribution of

the

Company’s securities

held-to-maturity

at September 30, 2021.


	Amortized Cost		Fair Value

	(in thousands)
Within one year	$	38,603	$	38,877
After one but within five years		1,790,437		1,804,982
After five but within ten years		1,382,937		1,363,400
More than ten years		—		—

Total	$	3,211,977	$	3,207,259

The weighted average remaining life of investment securities

held-to-maturity

at September 30, 2021 was 4.8 years. Included in the weighted average remaining life calculation at September 30, 2021 were $208,740,000 of U.S. Government Sponsored Enterprises obligations that are callable at the discretion of the issuer. The contractual maturities, which were used in the table above, of mortgage-backed securities, will differ from the actual maturities, due to the ability of the issuers to prepay underlying obligations. Also $67,000 of the securities are floating rate or adjustable rate and reprice prior to maturity.

As of September 30, 2021 and December 31, 2020, management concluded that the unrealized losses of its investment securities are temporary in nature since they are not related to the underlying credit quality of the issuers, and the Company does not intend to sell these debt securities and it is not more likely than not that it will be required to sell these debt securities before the anticipated recovery of their remaining amortized costs. In making its other-than- temporary impairment evaluation, the Company considered the fact that the principal and interest on these securities are from issuers that are investment grade.

The unrealized loss on U.S. Government Sponsored Enterprises, SBA Backed Securities, and U.S. Government Sponsored Enterprises Mortgage- Backed Securities related primarily to interest rates and not credit quality, and because the Company does not intend to sell any of these securities and it is not more likely than not that it will be required to sell these securities before the anticipated recovery of the remaining amortized cost, the Company does not consider these investments to be other-than-temporarily impaired at September 30, 2021 or December 31, 2020. In evaluating the underlying credit quality of a security, management considers several factors such as the credit rating of the obligor and the issuer, if applicable. Internal reviews of issuer financial statements are performed as deemed necessary.

The following table shows the temporarily impaired securities of the Company’s

held-to-maturity

portfolio September 30, 2021. This table shows the unrealized market loss of securities that have been in a continuous unrealized loss position for 12 months or less and a continuous loss position for 12 months or longer. There are 149 and 31 securities that are temporarily impaired for less than 12 months and for 12 months or longer, respectively, out of a total of 651 holdings at September 30, 2021.


	September 30, 2021
	Less Than 12 Months				12 Months or Longer				Total

Temporarily Impaired Investments	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses

	(in thousands)
US Government Sponsored Enterprises	$	194,263	$	2,579	$	146,298	$	2,444	$	340,561	$	5,023
SBA Backed Securities		—		—		—		—		—		—
U.S. Government Agency and Sponsored Enterprise Mortgage-Backed Securities		1,585,765		28,423		107,977		3,699		1,693,742		32,122

Total temporarily impaired securities	$	1,780,028	$	31,002	$	254,275	$	6,143	$	2,034,303	$	37,145

The following table shows the temporarily impaired securities of the Company’s

held-to-maturity

portfolio at December 31, 2020. This table shows the unrealized market loss of securities that have been in a continuous unrealized loss position for less than 12 months and a continuous loss position for 12 months or longer. There are 53 and 0 securities that are temporarily impaired for less than 12 months and for 12 months or longer, respectively, out of a total of 600 holdings at December 31, 2020.


	December 31, 2020
	Less Than 12 Months				12 Months or Longer				Total

Temporarily Impaired Investments	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses

	(in thousands)
U.S. Government Sponsored Enterprises	$	162,870	$	866	$	—	$	—	$	162,870	$	866
SBA Backed Securities		—		—		—		—		—		—
U.S. Government Agency and Sponsored Enterprise Mortgage-Backed Securities		302,401		1,032		—		—		302,401		1,032

Total temporarily impaired securities	$	465,271	$	1,898	$	—	$	—	$	465,271	$	1,898