Investment securities

3 Months Ended

Mar. 31, 2021

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, 2021
Investment securities available for sale:
U.S. Treasury and federal agencies	$	6,851	$	163	$	1	$	7,013
Mortgage-backed securities:
Government issued or guaranteed		4,051,580		174,154		645		4,225,089
Privately issued		16		—		—		16
Other debt securities		136,439		2,295		6,415		132,319
		4,194,886		176,612		7,061		4,364,437
Investment securities held to maturity:
U.S. Treasury and federal agencies		3,000		—		—		3,000
Obligations of states and political subdivisions		851		4		—		855
Mortgage-backed securities:
Government issued or guaranteed		1,697,992		79,650		1,623		1,776,019
Privately issued		73,496		11,288		17,244		67,540
Other debt securities		2,796		—		—		2,796
		1,778,135		90,942		18,867		1,850,210
Total debt securities	$	5,973,021	$	267,554	$	25,928	$	6,214,647
Equity and other securities:
Readily marketable equity — at fair value	$	68,983	$	13,012	$	203	$	81,792
Other — at cost		386,303		—		—		386,303
Total equity and other securities	$	455,286	$	13,012	$	203	$	468,095
December 31, 2020
Investment securities available for sale:
U.S. Treasury and federal agencies	$	9,154	$	198	$	14	$	9,338
Mortgage-backed securities:
Government issued or guaranteed		4,475,406		208,787		755		4,683,438
Privately issued		16		—		—		16
Other debt securities		136,451		1,664		8,301		129,814
		4,621,027		210,649		9,070		4,822,606
Investment securities held to maturity:
U.S. Treasury and federal agencies		2,999		—		—		2,999
Obligations of states and political subdivisions		1,531		9		—		1,540
Mortgage-backed securities:
Government issued or guaranteed		1,664,443		100,176		11		1,764,608
Privately issued		77,155		11,056		17,938		70,273
Other debt securities		2,861		—		—		2,861
		1,748,989		111,241		17,949		1,842,281
Total debt securities	$	6,370,016	$	321,890	$	27,019	$	6,664,887
Equity and other securities:
Readily marketable equity — at fair value	$	67,891	$	25,094	$	—	$	92,985
Other — at cost		381,117		—		—		381,117
Total equity and other securities	$	449,008	$	25,094	$	—	$	474,102

3. Investment securities, continued

There were no significant gross realized gains or losses from sales of investment securities for the quarters ended March 31, 2021 and 2020.  Unrealized losses on equity securities were $12 million and $21 million during the three months ended March 31, 2021 and 2020, respectively.  

At March 31, 2021, 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	$	2,482		2,501
Due after one year through five years		12,030		12,439
Due after five years through ten years		98,778		99,066
Due after ten years		30,000		25,326
		143,290		139,332
Mortgage-backed securities available for sale		4,051,596		4,225,105
	$	4,194,886		4,364,437
Debt securities held to maturity:
Due in one year or less	$	3,676		3,678
Due after one year through five years		175		177
Due after ten years		2,796		2,796
		6,647		6,651
Mortgage-backed securities held to maturity		1,771,488		1,843,559
	$	1,778,135		1,850,210

 3. Investment securities, continued

A summary of investment securities that as of March 31, 2021 and December 31, 2020 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, 2021
Investment securities available for sale:
U.S. Treasury and federal agencies	$	299		(1	)		—		—
Mortgage-backed securities:
Government issued or guaranteed		1,825		(8	)		25,724		(637	)
Other debt securities		2,401		(23	)		65,209		(6,392	)
		4,525		(32	)		90,933		(7,029	)
Investment securities held to maturity:
Mortgage-backed securities:
Government issued or guaranteed		199,549		(1,609	)		1,686		(14	)
Privately issued		—		—			51,443		(17,244	)
		199,549		(1,609	)		53,129		(17,258	)
Total	$	204,074		(1,641	)		144,062		(24,287	)
December 31, 2020
Investment securities available for sale:
U.S. Treasury and federal agencies	$	985		(14	)		—		—
Mortgage-backed securities:
Government issued or guaranteed		18,687		(356	)		16,556		(399	)
Other debt securities		16,055		(181	)		63,462		(8,120	)
		35,727		(551	)		80,018		(8,519	)
Investment securities held to maturity:
Mortgage-backed securities:
Government issued or guaranteed		2,039		(11	)		—		—
Privately issued		—		—			52,418		(17,938	)
		2,039		(11	)		52,418		(17,938	)
Total	$	37,766		(562	)		132,436		(26,457	)

The Company owned 281 individual debt securities with aggregate gross unrealized losses of $26 million at March 31, 2021. Based on a review of each of the securities in the investment securities portfolio at March 31, 2021, the Company concluded that it expected to recover the amortized cost basis of its investment.  As of March 31, 2021, 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, 2021, the Company has not identified events or changes in circumstances which may have a significant adverse effect on the fair value of the $386 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, 2021 or December 31, 2020, as the substantial majority of such investment securities are obligations backed by the U.S. government or its agencies.