
Debt securities AFS (In thousands)	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Fair Value
March 31, 2021:
Obligations of states and political subdivisions	$	278,676	$	19,637	$	—	$	298,313
U.S. Government sponsored entities' asset-backed securities	800,312		20,955		6,358		814,909
Corporate debt securities	2,000		62		—		2,062
Total	$	1,080,988	$	40,654	$	6,358	$	1,115,284


Debt securities AFS (In thousands)	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Fair Value
December 31, 2020:
Obligations of states and political subdivisions	$	279,245	$	25,973	$	—	$	305,218
U.S. Government sponsored entities' asset-backed securities	726,589		26,248		728		752,109
Corporate debt securities	2,000		14		—		2,014
Total	$	1,007,834	$	52,235	$	728	$	1,059,341

Park’s U.S. Government sponsored entities' asset-backed securities consist primarily of 15-year residential mortgage-backed securities and collateralized mortgage obligations.


	Unrealized loss position for less than 12 months				Unrealized loss position for 12 months or longer				Total
(In thousands)	Fair value		Unrealized losses		Fair value		Unrealized losses		Fair value		Unrealized losses
Debt securities AFS
U.S. Government sponsored entities' asset-backed securities	$	220,681	$	6,326	$	4,255	$	32	$	224,936	$	6,358
Total	$	220,681	$	6,326	$	4,255	$	32	$	224,936	$	6,358


	Unrealized loss position for less than 12 months				Unrealized loss position for 12 months or longer				Total
(In thousands)	Fair value		Unrealized losses		Fair value		Unrealized losses		Fair value		Unrealized losses
Debt securities AFS
U.S. Government sponsored entities' asset-backed securities	$	86,393	$	695	$	4,727	$	33	$	91,120	$	728
Total	$	86,393	$	695	$	4,727	$	33	$	91,120	$	728

Unrealized losses on U.S. Government sponsored entities' asset-based securities have not been recognized into income as they represent negative adjustments to fair value relative to the rate of interest paid on the securities and not losses related to the creditworthiness of the issuer. Management does not intend to sell, and it is not more likely than not that management would be required to sell, the securities prior to their anticipated recovery. Management believes the value will recover as the securities approach maturity or market rates change.

There was no allowance for credit losses recorded for AFS debt securities at March 31, 2021. Additionally, for the three-months ended March 31, 2021 and 2020, there were no credit-related investment impairment losses recognized.

The amortized cost and estimated fair value of investments in debt securities at March 31, 2021, are shown in the following table by contractual maturity, except for asset-backed securities, which are shown as a single total, due to the unpredictability of the timing of principal repayments.


Debt securities AFS (In thousands)	Amortized cost		Fair value		Tax equivalent yield (1)

U.S. Government sponsored entities' asset-backed securities	$	800,312	$	814,909	1.92	%

Corporate debt securities
Due five through ten years	$	2,000	$	2,062	4.00	%

Obligations of state and political subdivisions:
Due five through ten years	$	96,354	$	103,192	3.75	%
Due over ten years	182,322		195,121		3.67	%
Total (1)	$	278,676	$	298,313	3.70	%

(1) The tax equivalent yield for certain obligations of state and political subdivisions includes the effects of a taxable equivalent adjustment using a 21% federal corporate income tax rate.