Investment securities

3 Months Ended

Mar. 31, 2022

Investments Debt And Equity Securities [Abstract]

Investment securities

3. Investment securities

The amortized cost and estimated fair value of investment securities were as follows:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
	(In thousands)
March 31, 2022
Investment securities available for sale:
U.S. Treasury and federal agencies	$	2,838,987	$	707	$	49,977	$	2,789,717
Mortgage-backed securities:
Government issued or guaranteed		2,820,570		14,599		39,992		2,795,177
Other debt securities		124,140		996		4,831		120,305
		5,783,697		16,302		94,800		5,705,199
Investment securities held to maturity:
U.S. Treasury and federal agencies		3,038		—		24		3,014
Obligations of states and political subdivisions		175		—		—		175
Mortgage-backed securities:
Government issued or guaranteed		3,117,175		4,830		141,477		2,980,528
Privately issued		57,751		10,309		11,555		56,505
Other debt securities		2,487		—		—		2,487
		3,180,626		15,139		153,056		3,042,709
Total debt securities	$	8,964,323	$	31,441	$	247,856	$	8,747,908
Equity and other securities:
Readily marketable equity — at fair value	$	78,042	$	4,653	$	1,530	$	81,165
Other — at cost		389,842		—		—		389,842
Total equity and other securities	$	467,884	$	4,653	$	1,530	$	471,007
Balance — December 31, 2021
Investment securities available for sale:
U.S. Treasury and federal agencies	$	682,267	$	229	$	3,806	$	678,690
Mortgage-backed securities:
Government issued or guaranteed		3,042,771		113,102		561		3,155,312
Other debt securities		124,309		1,974		4,481		121,802
		3,849,347		115,305		8,848		3,955,804
Investment securities held to maturity:
U.S. Treasury and federal agencies		3,052		—		9		3,043
Obligations of states and political subdivisions		177		2		—		179
Mortgage-backed securities:
Government issued or guaranteed		2,667,328		49,221		8,376		2,708,173
Privately issued		61,555		10,520		14,742		57,333
Other debt securities		2,562		—		—		2,562
		2,734,674		59,743		23,127		2,771,290
Total debt securities	$	6,584,021	$	175,048	$	31,975	$	6,727,094
Equity and other securities:
Readily marketable equity — at fair value	$	73,774	$	4,460	$	594	$	77,640
Other — at cost		387,742		—		—		387,742
Total equity and other securities	$	461,516	$	4,460	$	594	$	465,382

3. Investment securities, continued

There were no significant gross realized gains or losses from sales of investment securities for the quarters ended March 31, 2022 and 2021. Unrealized losses on equity securities were $1 million and $12 million during the three months ended March 31, 2022 and 2021, respectively.  

At March 31, 2022, the amortized cost and estimated fair value of debt securities by contractual maturity were as follows:

	Amortized Cost		Estimated Fair Value
	(In thousands)
Debt securities available for sale:
Due in one year or less	$	6,955	$	6,947
Due after one year through five years		2,895,828		2,846,337
Due after five years through ten years		30,344		30,018
Due after ten years		30,000		26,720
		2,963,127		2,910,022
Mortgage-backed securities available for sale		2,820,570		2,795,177
	$	5,783,697	$	5,705,199
Debt securities held to maturity:
Due in one year or less	$	3,213	$	3,189
Due after ten years		2,487		2,487
		5,700		5,676
Mortgage-backed securities held to maturity		3,174,926		3,037,033
	$	3,180,626	$	3,042,709

 3. Investment securities, continued

A summary of investment securities that as of March 31, 2022 and December 31, 2021 had been in a continuous unrealized loss position for less than twelve months and those that had been in a continuous unrealized loss position for twelve months or longer follows:

	Less Than 12 Months				12 Months or More
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(In thousands)
March 31, 2022
Investment securities available for sale:
U.S. Treasury and federal agencies	$	2,341,892	$	49,970	$	293	$	7
Mortgage-backed securities:
Government issued or guaranteed		2,099,805		39,425		19,599		567
Other debt securities		7,357		69		67,888		4,762
		4,449,054		89,464		87,780		5,336
Investment securities held to maturity:
U.S. Treasury and federal agencies		3,014		24		—		—
Mortgage-backed securities:
Government issued or guaranteed		2,639,956		141,419		1,178		58
Privately issued		—		—		38,536		11,555
		2,642,970		141,443		39,714		11,613
Total	$	7,092,024	$	230,907	$	127,494	$	16,949
December 31, 2021
Investment securities available for sale:
U.S. Treasury and federal agencies	$	598,566	$	3,806	$	—	$	—
Mortgage-backed securities:
Government issued or guaranteed		10,111		54		20,824		507
Other debt securities		3,760		74		66,419		4,407
		612,437		3,934		87,243		4,914
Investment securities held to maturity:
U.S. Treasury and federal agencies		3,043		9		—		—
Mortgage-backed securities:
Government issued or guaranteed		1,372,236		8,356		1,251		20
Privately issued		—		—		43,692		14,742
		1,375,279		8,365		44,943		14,762
Total	$	1,987,716	$	12,299	$	132,186	$	19,676

The Company owned 1,217 individual debt securities with aggregate gross unrealized losses of $248 million at March 31, 2022. Based on a review of each of the securities in the investment securities portfolio at March 31, 2022, the Company concluded that it expected to recover the amortized cost basis of its investment. As of March 31, 2022, the Company does not intend to sell nor is it anticipated that it would be required to sell any of its impaired investment securities at a loss. At March 31, 2022, the Company has not identified events or changes in circumstances which may have a significant adverse effect on the fair value of the $390 million of cost method equity securities.

The Company estimated no material allowance for credit losses for its investment securities classified as held-to-maturity at March 31, 2022 or December 31, 2021, as the substantial majority of such investment securities are obligations backed by the U.S. government or its agencies.