Investment securities are designated as AFS, HTM, or equity on the consolidated balance sheets at the time of purchase. The amortized cost and fair values of AFS and HTM securities at June 30, 2022 were as follows:


($ in Thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses)		Fair Value


AFS investment securities
U. S. Treasury securities	$	124,365	$	—	$	(11,256)	$	113,109
Agency securities	15,000		—		(1,041)		13,959
Obligations of state and political subdivisions (municipal securities)	361,712		648		(3,518)		358,842
Residential mortgage-related securities
FNMA / FHLMC	1,959,641		547		(148,585)		1,811,603
GNMA	87,779		—		(1,542)		86,238

Commercial mortgage-related securities
FNMA / FHLMC	19,207		—		(601)		18,606
GNMA	108,153		—		(2,473)		105,680
Asset backed securities
FFELP	168,357		—		(7,092)		161,264
SBA	5,287		40		(45)		5,281

Other debt securities	3,000		—		(71)		2,929
Total AFS investment securities	$	2,852,501	$	1,234	$	(176,224)	$	2,677,511
HTM investment securities
U. S. Treasury securities	$	998	$	—	$	(44)	$	955
Obligations of state and political subdivisions (municipal securities)	1,717,627		4,002		(161,116)		1,560,514
Residential mortgage-related securities
FNMA / FHLMC	967,421		34,108		(125,444)		876,085
GNMA	42,248		37		(1,637)		40,649
Private-label	375,638		12,693		(54,490)		333,841
Commercial mortgage-related securities
FNMA/FHLMC	762,086		16,835		(131,851)		647,070
GNMA	79,250		799		(4,970)		75,079
Total HTM investment securities	$	3,945,269	$	68,474	$	(479,551)	$	3,534,192

During the first quarter of 2022, the Corporation redesignated approximately $1.6 billion of mortgage-related securities from AFS to HTM. The reclassification of these investment securities was accounted for at fair value. Management elected to transfer these investment securities as the Corporation has the positive intent and ability to hold these investment securities to maturity. See Note 16 for additional information on the unrealized losses on investment securities transferred from AFS to HTM.

The amortized cost and fair values of AFS and HTM securities at December 31, 2021 were as follows:


($ in Thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses)		Fair Value


AFS investment securities
U. S. Treasury securities	$	124,291	$	—	$	(1,334)	$	122,957
Agency securities	15,000		—		(103)		14,897
Obligations of state and political subdivisions (municipal securities)	381,517		18,940		—		400,457
Residential mortgage-related securities
FNMA / FHLMC	2,709,399		3,729		(21,249)		2,691,879
GNMA	66,189		1,591		—		67,780
Private-label	332,028		31		(2,335)		329,724
Commercial mortgage-related securities
FNMA / FHLMC	357,240		2,686		(9,302)		350,623
GNMA	165,439		1,360		—		166,799
Asset backed securities
FFELP	177,974		475		(1,123)		177,325
SBA	6,594		39		(54)		6,580
Other debt securities	3,000		—		(6)		2,994
Total AFS investment securities	$	4,338,671	$	28,850	$	(35,506)	$	4,332,015
HTM investment securities
U. S. Treasury securities	$	1,000	$	1	$	—	$	1,001
Obligations of state and political subdivisions (municipal securities)	1,628,759		113,179		(1,951)		1,739,988
Residential mortgage-related securities
FNMA / FHLMC	34,347		1,792		—		36,139
GNMA	48,053		1,578		—		49,631
Commercial mortgage-related securities
FNMA / FHLMC	425,937		122		(6,659)		419,400
GNMA	100,907		1,799		(200)		102,506
Total HTM investment securities	$	2,239,003	$	118,471	$	(8,809)	$	2,348,664

Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. The expected maturities of AFS and HTM securities at June 30, 2022, are shown below:


	AFS					HTM
($ in Thousands)	Amortized Cost		Fair Value			Amortized Cost		Fair Value
Due in one year or less	$	6,905	$	6,895		$	15,582	$	15,627
Due after one year through five years	98,473		94,572			34,915		35,027
Due after five years through ten years	361,344		350,609			169,413		167,713
Due after ten years	37,355		36,762			1,498,715		1,343,101
Total debt securities	504,077		488,839			1,718,625		1,561,468
Residential mortgage-related securities
FNMA / FHLMC	1,959,641		1,811,603			967,421		876,085
GNMA	87,779		86,238			42,248		40,649
Private-label	—		—			375,638		333,841
Commercial mortgage-related securities
FNMA / FHLMC	19,207		18,606			762,086		647,070
GNMA	108,153		105,680			79,250		75,079
Asset backed securities
FFELP	168,357		161,264			—		—
SBA	5,287		5,281			—		—

Total investment securities	$	2,852,501	$	2,677,511		$	3,945,269	$	3,534,192
Ratio of fair value to amortized cost			93.9		%			89.6		%

On a quarterly basis, the Corporation refreshes the credit quality of each HTM security. The following table summarizes the credit quality indicators of HTM securities at amortized cost at June 30, 2022:


($ in Thousands)	AAA		AA		A		Not Rated		Total
U. S. Treasury securities	$	998	$	—	$	—	$	—	$	998
Obligations of state and political subdivisions (municipal securities)	799,925		908,098		8,710		894		1,717,627
Residential mortgage-related securities
FNMA / FHLMC	967,421		—		—		—		967,421
GNMA	42,248		—		—		—		42,248
Private-label	375,638		—		—		—		375,638
Commercial mortgage-related securities
FNMA / FHLMC	762,086		—		—		—		762,086
GNMA	79,250		—		—		—		79,250
Total HTM securities	$	3,027,567	$	908,098	$	8,710	$	894	$	3,945,269

The following table summarizes the credit quality indicators of HTM securities at amortized cost at December 31, 2021:


($ in Thousands)	AAA		AA		A		Not Rated		Total
U. S. Treasury securities	$	1,000	$	—	$	—	$	—	$	1,000
Obligations of state and political subdivisions (municipal securities)	702,399		914,591		10,873		896		1,628,759
Residential mortgage-related securities
FNMA / FHLMC	34,347		—		—		—		34,347
GNMA	48,053		—		—		—		48,053
Commercial mortgage-related securities
FNMA / FHLMC	425,937		—		—		—		425,937
GNMA	100,907		—		—		—		100,907
Total HTM securities	$	1,312,642	$	914,591	$	10,873	$	896	$	2,239,003

Investment securities gains (losses), net includes proceeds from the sale of AFS investment securities. The proceeds from the sale of AFS investment securities for the three and six months ended June 30, 2022 and 2021, are shown below:


	Three Months Ended Jun 30,				Six Months Ended Jun 30,
($ in Thousands)	2022		2021		2022		2021
Gross gains on AFS securities	$	—	$	386	$	21	$	421


Gross (losses) on AFS securities	(8)		(362)		(8)		(437)



Investment securities gains (losses), net	$	(8)	$	24	$	12	$	(16)
Proceeds from sales of AFS investment securities	$	327	$	107,412	$	1,061	$	158,708

During the second quarter of 2021, the Corporation sold $107 million of lower yielding FFELP student loan asset backed securities at an immaterial gain and reinvested the proceeds into higher yielding mortgage backed securities. During the first quarter of 2021, the Corporation sold $51 million of lower yielding U.S. Treasury and Agency securities at an immaterial loss to take advantage of the steeper yield curve by reinvesting the proceeds into similar but higher yielding, longer duration securities.

Accrued interest receivable on HTM securities totaled $18 million and $15 million at June 30, 2022 and December 31, 2021, respectively. Accrued interest receivable on AFS securities totaled $7 million and $9 million at June 30, 2022 and December 31, 2021, respectively. Accrued interest receivable on both HTM and AFS securities is included in interest receivable on the consolidated balance sheets. There was no interest income reversed for investments going into nonaccrual at both June 30, 2022 and 2021.

The allowance for credit losses on HTM securities was approximately $63,000 at June 30, 2022 and approximately $55,000 at December 31, 2021, attributable entirely to the Corporation's municipal securities, included in HTM investment securities, net, at amortized cost on the consolidated balance sheets. The Corporation also holds U.S. Treasury, municipal and mortgage-related securities issued by the U.S. government or a GSE which are backed by the full faith and credit of the U.S. government and, as a result, no allowance for credit losses has been recorded related to these securities.

For comparative purposes, the following represents gross unrealized losses and the related fair value of AFS and HTM securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at December 31, 2021:


	Less than 12 months					12 months or more					Total
($ in Thousands)	Number of Securities	Unrealized (Losses)		Fair Value		Number of Securities	Unrealized (Losses)		Fair Value		Unrealized (Losses)		Fair Value
AFS investment securities
U.S. Treasury securities	7	$	(1,334)	$	122,957	—	$	—	$	—	$	(1,334)	$	122,957
Agency securities	1	(103)		14,897		—	—		—		(103)		14,897

Residential mortgage-related securities
FNMA / FHLMC	74	(21,249)		2,172,837		—	—		—		(21,249)		2,172,837

Private-label	12	(2,335)		248,617		—	—		—		(2,335)		248,617

FNMA / FHLMC commercial mortgage-related securities	19	(9,302)		328,568		—	—		—		(9,302)		328,568
Asset backed securities
FFELP	4	(256)		64,282		8	(867)		62,576		(1,123)		126,858
SBA	—	—		—		9	(54)		3,902		(54)		3,902
Other debt securities	3	(6)		2,994		—	—		—		(6)		2,994

Total	120	$	(34,586)	$	2,955,152	17	$	(920)	$	66,478	$	(35,506)	$	3,021,630
HTM investment securities
Obligations of state and political subdivisions (municipal securities)	49	$	(1,951)	$	112,038	—	$	—	$	—	$	(1,951)	$	112,038


Commercial mortgage-related securities
FNMA/FHLMC	18	(6,272)		388,072		1	(387)		10,775		(6,659)		398,847
GNMA	5	(200)		33,468		—	—		—		(200)		33,468
Total	72	$	(8,422)	$	533,577	1	$	(387)	$	10,775	$	(8,809)	$	544,352

The Corporation reviews the AFS investment securities portfolio on a quarterly basis to monitor its credit exposure. A determination as to whether a security’s decline in fair value is the result of credit risk takes into consideration numerous factors and the relative significance of any single factor can vary by security. Some factors the Corporation may consider in this impairment analysis include the extent to which the security has been in an unrealized loss position, the change in security rating, financial condition and near-term prospects of the issuer, as well as the security and industry specific economic conditions.

Based on the Corporation’s evaluation, management does not believe any unrealized losses at June 30, 2022 represent credit deterioration as these unrealized losses are primarily attributable to changes in interest rates and the current market conditions. The Corporation does not intend to sell nor does it believe that it will be required to sell the securities in an unrealized loss position before recovery of their amortized cost basis.

FHLB and Federal Reserve Bank stocks: The Corporation is required to maintain Federal Reserve Bank stock and FHLB stock as a member bank of both the Federal Reserve System and the FHLB, and in amounts as required by these institutions. These equity securities are “restricted” in that they can only be sold back to the respective institutions or another member institution at par. Therefore, they are less liquid than other marketable equity securities and their fair value is equal to amortized cost. The Corporation had FHLB stock of $151 million and $82 million at June 30, 2022 and December 31, 2021, respectively. The Corporation had Federal Reserve Bank stock of $87 million at both June 30, 2022 and December 31, 2021. Accrued interest receivable on FHLB stock totaled $1 million and approximately $975,000 at June 30, 2022 and December 31, 2021, respectively. There was no accrued interest receivable on Federal Reserve Bank stock at both June 30, 2022 and December 31, 2021. Accrued interest receivable on both FHLB stock and Federal Reserve Bank stock is included in interest receivable on the consolidated balance sheets.

Equity securities with readily determinable fair values: The Corporation's portfolio of equity securities with readily determinable fair values is primarily comprised of CRA Qualified Investment mutual funds and other mutual funds. At June 30, 2022 and December 31, 2021, the Corporation had equity securities with readily determinable fair values of $6 million and $5 million, respectively.