Investment Securities

12 Months Ended

Dec. 31, 2020

Investments, Debt and Equity Securities [Abstract]

The following table presents our investment securities:


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(Dollars in millions)
December 31, 2020
Available-for-sale securities
Agency - Commercial	$	1,018	$	43	$	—	$	1,061
Agency - Residential	707		28		—		735
Corporate debt obligations	75		2		—		77
Municipal obligations	27		1		—		28
Other MBS	42		—		—		42
Certificate of deposit	1		—		—		1
Total available-for-sale securities (1)	$	1,870	$	74	$	—	$	1,944
Held-to-maturity securities
Agency - Commercial	$	193	$	7	$	—	$	200
Agency - Residential	184		9		—		193
Total held-to-maturity securities (1)	$	377	$	16	$	—	$	393
December 31, 2019
Available-for-sale securities
Agency - Commercial	$	948	$	2	$	(3)	$	947
Agency - Residential	1,015		4		(4)		1,015
Corporate debt obligations	76		1		—		77
Municipal obligations	31		—		—		31
Other MBS	44		1		—		45
Certificate of deposit	1		—		—		1
Total available-for-sale securities (1)	$	2,115	$	8	$	(7)	$	2,116
Held-to-maturity securities
Agency - Commercial	$	306	$	—	$	(1)	$	305
Agency - Residential	292		3		(1)		294
Total held-to-maturity securities (1)	$	598	$	3	$	(2)	$	599

(1)There were no securities of a single issuer, which are not governmental or government-sponsored, that exceeded 10 percent of stockholders’ equity at December 31, 2020 or December 31, 2019.

We evaluate our securities portfolio each quarter to determine if any security's value has declined below amortized cost for impairment (for further information on our policy for assessing impairment on our security portfolio, see Note 1 - Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies). We had no unrealized credit losses during the years ended December 31, 2020, 2019 and 2018.

Available-for-sale securities

We purchased $360 million of AFS securities, which were comprised of U.S. government sponsored agency MBS, certificates of deposit, and corporate debt obligations during the year ended December 31, 2020. We purchased $500 million of AFS securities, which included U.S. government sponsored agency MBS, corporate debt obligations and municipal obligations during the year ended December 31, 2019.

We had no sales of AFS securities during the year ended December 31, 2020. During the year ended December 31, 2019, we sold $432 million of AFS securities, which resulted in a gain of $7 million. We had no sales of U.S. government sponsored agency securities during the year ended December 31, 2018.

Held-to-maturity securities

There were no purchases or sales of HTM securities during the years ended December 31, 2020, December 31, 2019 and December 31, 2018.

The following table summarizes the unrealized loss positions on available-for-sale and held-to-maturity investment securities, by duration of the unrealized loss:


	Unrealized Loss Position with Duration 12 Months and Over					Unrealized Loss Position with Duration Under 12 Months
	Fair Value		Number of Securities	Unrealized Loss		Fair Value		Number of Securities	Unrealized Loss
	(Dollars in millions)
December 31, 2020
Available-for-sale securities
Agency - Commercial	$	3	1	$	—	$	7	2	$	—
Agency - Residential	—		—	—		—		1	—

Corporate debt obligations	—		—	—		10		3	—
Other mortgage-backed securities	—		—	—		—		1	—
Held-to-maturity securities

Agency - Residential	—		—	—		2		3	—
December 31, 2019
Available-for-sale securities
Agency - Commercial	$	148	17	$	(3)	$	303	19	$	—
Agency - Residential	266		26	(3)		148		14	(1)
Municipal obligations	8		3	—		—		—	—

Held-to-maturity securities
Agency - Commercial	$	148	13	$	(1)	$	85	6	$	—
Agency - Residential	35		7	(1)		38		10	—

Unrealized losses on available-for-sale securities have not been recognized into income because almost all of the portfolio held by us are issued by U.S. government entities and agencies. These securities are either explicitly or implicitly guaranteed by the U.S. government, are highly rated by major rating agencies, and have a long history of no credit losses. The remaining unrealized losses on available-for-sale securities are municipal securities and corporate debt obligations, all of which are considered investment grade or are de minimis. The fair value is expected to recover as the bonds approach maturity.

The following table shows the amortized cost and estimated fair value of securities by contractual maturity:


	Investment Securities Available-for-Sale						Investment Securities Held-to-Maturity
	Amortized Cost		Fair Value		Weighted-Average Yield (1)		Amortized Cost		Fair Value		Weighted-Average Yield (1)
	(Dollars in millions)
December 31, 2020
Due in one year or less	$	5	$	5	2.22	%	$	—	$	—	—	%
Due after one year through five years	9		10		2.83	%	7		8		2.44	%
Due after five years through 10 years	123		127		3.95	%	7		8		2.37	%
Due after 10 years	1,733		1,802		2.34	%	363		377		2.41	%
Total	$	1,870	$	1,944			$	377	$	393

(1) Weighted-average yields are based on amortized cost weighted for the contractual maturity of each security.

We pledge investment securities, primarily agency collateralized and municipal taxable mortgage obligations, to collateralize lines of credit and/or borrowings. We had pledged investment securities of $202 million and, $874 million, at December 31, 2020 and 2019 respectively.