As of December 31, 2020, the following debt securities and other investments were included in short-term investments and long-term investments on the Consolidated Balance Sheet and recorded at fair value:

	Amortized		Gross Unrealized					Fair
(In thousands)	Cost		Gains		Losses			Value
Corporate bonds	$	11,762	$	123	$	—		$	11,885
Municipal fixed-rate bonds		2,854		30		—			2,884
Asset-backed bonds		6,634		74		—			6,708
Mortgage/Agency-backed bonds		11,536		114		(6	)		11,644
U.S. government bonds		9,763		112		—			9,875
Foreign government bonds		1,334		4		(1	)		1,337
Commercial Paper		250		—		—			250
Other		533		—		—			533
Available-for-sale debt securities held at fair value	$	44,666	$	457	$	(7	)	$	45,116

As of December 31, 2019, the following debt securities and other investments were included in short-term investments and long-term investments on the Consolidated Balance Sheet and recorded at fair value:

	Amortized		Gross Unrealized					Fair
(In thousands)	Cost		Gains		Losses			Value
Corporate bonds	$	9,304	$	80	$	—		$	9,384
Municipal fixed-rate bonds		930		—		—			930
Asset-backed bonds		6,867		26		(3	)		6,890
Mortgage/Agency-backed bonds		6,944		26		(8	)		6,962
U.S. government bonds		12,311		21		(9	)		12,323
Foreign government bonds		372		—		(1	)		371
Variable rate demand notes		800		—		—			800
Available-for-sale debt securities held at fair value	$	37,528	$	153	$	(21	)	$	37,660

As of December 31, 2020, our debt securities had the following contractual maturities:

(In thousands)	Corporate bonds		Municipal fixed-rate bonds		Asset-backed bonds		Mortgage / Agency-backed bonds		U.S. government bonds		Foreign government bonds		Commercial paper		Other
Less than one year	$	1,477	$	96	$	144	$	63	$	—	$	75	$	250	$	533
One to two years		2,007		1,245		300		2,129		5,122		462		—		—
Two to three years		7,013		1,246		622		2,940		4,526		498		—		—
Three to five years		1,388		297		3,658		183		227		302		—		—
Five to ten years		—		—		1,241		2,095		—		—		—		—
More than ten years		—		—		743		4,234		—		—		—		—
Total	$	11,885	$	2,884	$	6,708	$	11,644	$	9,875	$	1,337	$	250	$	533

Actual maturities may differ from contractual maturities as some borrowers have the right to call or prepay obligations with or without call or prepayment penalties.

Realized gains and losses on sales of securities are computed under the specific identification method. The following table presents gross realized gains and losses related to our debt securities for the years ended December 31, 2020, 2019 and 2018:

The Company’s investment policy provides limitations for issuer concentration, which limits, at the time of purchase, the concentration in any one issuer to 5% of the market value of the total investment portfolio. The Company did not purchase any available-for-sale debt with credit deterioration during the years ended December 31, 2020, 2019 and 2018.

The following table presents the breakdown of debt securities and other investments with unrealized losses as of December 31, 2020:

	Continuous Unrealized Loss Position for Less than 12 Months					Continuous Unrealized Loss Position for 12 Months or Greater				Total
(In thousands)	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Corporate bonds	$	336	$	—		$	—	$	—	$	336	$	—
Municipal fixed-rate bonds		310		—			—		—		310		—
Asset-backed bonds		2		—			—		—		2		—
Mortgage/Agency-backed bonds		2,078		(6	)		—		—		2,078		(6	)
U.S. government bonds		350		—			—		—		350		—
Foreign government bonds		302		(1	)		—		—		302		(1	)
Total	$	3,378	$	(7	)	$	—	$	—	$	3,378	$	(7	)

The following table presents the breakdown of debt securities and other investments with unrealized losses as of December 31, 2019:

	Continuous Unrealized Loss Position for Less than 12 Months					Continuous Unrealized Loss Position for 12 Months or Greater					Total
(In thousands)	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
Corporate bonds	$	203	$	—		$	—	$	—		$	203	$	—
Municipal fixed-rate bonds		930		—			—		—			930		—
Asset-backed bonds		797		(3	)		—		—			797		(3	)
Mortgage/Agency-backed bonds		2,594		(6	)		136		(2	)		2,730		(8	)
U.S. government bonds		4,070		(9	)		—		—			4,070		(9	)
Foreign government bonds		371		(1	)		—		—			371		(1	)
Total	$	8,965	$	(19	)	$	136	$	(2	)	$	9,101	$	(21	)

The decrease in unrealized losses during 2020 resulted from changes in market positions associated with our fixed income portfolio.

Marketable equity securities consist of publicly traded stock, funds and certain other investments measured at fair value or cost, where appropriate.

During the three months ended March 31, 2019, an outstanding note receivable of $4.3 million was repaid and reissued in the form of debt and equity. Of the outstanding $4.3 million, $3.4 million was issued as an equity investment, which represented a non-cash investing activity. This equity investment, which does not have a readily determinable fair value, was recorded using the measurement alternative. Under the measurement alternative, equity investments that do not have a readily determinable fair value can be recorded at cost less impairment, if any, adjusted for observable price changes for an identical or similar investment. The carrying value of this investment under the measurement alternative was $3.4 million as of December 31, 2019. During the year ended December 31, 2020, impairment charges totaling $2.6 million were recorded related to this equity investment and are included in net investment gain (loss) on the Consolidated Statement of Income (Loss). As a result, the carrying value of this investment was $0.8 million as of December 31, 2020. The remaining amount, $0.9 million of the original $4.3 million note receivable, was reissued as a new note receivable, which is included in long-term investments on the Consolidated Balance Sheets as of December 31, 2020 and December 31, 2019, and represented a non-cash investing activity during the year ended December 31, 2019. No impairment charge was recognized related to the note receivable as it is a secured loan.

Realized and unrealized gains and losses for our marketable equity securities for the year ended December 31, 2020, 2019 and 2018 were as follows:

As of December 31, 2020 and 2019, gross unrealized losses related to individual investments in a continuous loss position for twelve months or longer were not material.

U.S. GAAP establishes a three-level valuation hierarchy based upon observable and unobservable inputs for fair value measurement of financial instruments:

• Level 1 – Observable outputs; values based on unadjusted quoted prices for identical assets or liabilities in an active market;

• Level 2 – Significant inputs that are observable; values based on quoted prices in markets that are not active or model inputs that are observable either directly or indirectly;

• Level 3 – Significant unobservable inputs; values based on prices or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement; inputs could include information supplied by investees.

The Company’s cash equivalents and investments held at fair value are categorized into this hierarchy as follows:

	Fair Value Measurements as of December 31, 2020 Using
(In thousands)	Fair Value		Quoted Prices in Active Market for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash equivalents
Money market funds	$	497	$	497	$	—	$	—
U.S. government bonds		350		350		—		—
Available-for-sale debt securities
Corporate bonds		11,885		—		11,885		—
Municipal fixed-rate bonds		2,884		—		2,884		—
Asset-backed bonds		6,708		—		6,708		—
Mortgage/Agency-backed bonds		11,644		—		11,644		—
U.S. government bonds		9,875		9,875		—		—
Foreign government bonds		1,337		—		1,337		—
Commercial paper		250		—		250		—
Other investments		533		—		—		533
Marketable equity securities
Marketable equity securities – various industries		10,963		10,963		—		—
Deferred compensation plan assets		23,891		23,891		—		—
Other investments		1,400		1,400		—		—
Total	$	82,217	$	46,976	$	34,708	$	533

	Fair Value Measurements as of December 31, 2019 Using
(In thousands)	Fair Value		Quoted Prices in Active Market for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash equivalents
Money market funds	$	1,309	$	1,309	$	—	$	—
Available-for-sale debt securities
Corporate bonds		9,384		—		9,384		—
Municipal fixed-rate bonds		930		—		930		—
Asset-backed bonds		6,890		—		6,890		—
Mortgage/Agency-backed bonds		6,962		—		6,962		—
U.S. government bonds		12,323		12,323		—		—
Foreign government bonds		371		—		371		—
Variable rate demand notes		800		—		800		—
Marketable equity securities
Marketable equity securities – various industries		35,501		35,501		—		—
Equity in escrow		298		298		—		—
Deferred compensation plan assets		21,698		21,698		—		—
Other investments		2,442		2,442		—		—
Total	$	98,908	$	73,571	$	25,337	$	—

The fair value of our Level 2 securities is calculated using a weighted average market price for each security. Market prices are obtained from a variety of industry standard data providers, large financial institutions and other third-party sources. These multiple market prices are used as inputs into a distribution-curve-based algorithm to determine the daily market value of each security.

The fair value of Level 3 securities is calculated based on unobservable inputs. Quantitative information with respect to unobservable inputs consisted of third-party valuations performed in accordance with ASC 820 – Fair Value Measurement. Inputs used in preparing the third-party valuation included the following assumptions, among others: estimated discount rates and fair market yields.

Our variable rate demand notes have a structure that implies a standard expected market price. The frequent interest rate resets make it reasonable to expect the price to stay at par. These securities are priced at the expected market price.