As of December 31, 2019, we held the following debt securities and other investments, 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, 2018, we held the following debt securities and other investments, recorded at fair value:

	Amortized		Gross Unrealized					Fair
(In thousands)	Cost		Gains		Losses			Value
Corporate bonds	$	20,777	$	19	$	(112	)	$	20,684
Municipal fixed-rate bonds		1,339		—		(26	)		1,313
Asset-backed bonds		5,230		5		(14	)		5,221
Mortgage/Agency-backed bonds		3,833		2		(44	)		3,791
U.S. government bonds		9,271		1		(66	)		9,206
Foreign government bonds		592		—		(8	)		584
Available-for-sale debt securities held at fair value	$	41,042	$	27	$	(270	)	$	40,799

As of December 31, 2019, 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
Less than one year	$	4,005	$	—	$	396	$	—	$	—	$	—
One to two years		4,120		930		760		213		1,347		—
Two to three years		967		—		1,632		1,424		9,344		—
Three to five years		292		—		2,092		494		1,632		371
Five to ten years		—		—		1,719		792		—		—
More than ten years		—		—		291		4,039		—		—
Total	$	9,384	$	930	$	6,890	$	6,962	$	12,323	$	371

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, 2019, 2018 and 2017:

Our 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 our total investment portfolio.

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	)
Marketable equity securities		371		(1	)		—		—			371		(1	)
Total	$	8,965	$	(19	)	$	136	$	(2	)	$	9,101	$	(21	)

The following table presents the breakdown of debt securities and other investments with unrealized losses as of December 31, 2018:

	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	$	11,129	$	(60	)	$	3,608	$	(52	)	$	14,737	$	(112	)
Municipal fixed-rate bonds		—		—			1,136		(26	)		1,136		(26	)
Asset-backed bonds		1,874		(2	)		1,257		(12	)		3,131		(14	)
Mortgage/Agency-backed bonds		1,021		(5	)		1,918		(39	)		2,939		(44	)
U.S. government bonds		6,527		(48	)		537		(18	)		7,064		(66	)
Foreign government bonds		584		(8	)		—		—			584		(8	)
Total	$	21,135	$	(123	)	$	8,456	$	(147	)	$	29,591	$	(270	)

The decrease in unrealized losses during 2019, as reflected in the table above, results from changes in market positions associated with our fixed income portfolio.

Our marketable equity securities consist of publicly traded stocks or funds measured at fair value.

Prior to January 1, 2018, our marketable equity securities were classified as available-for-sale. Realized gains and losses on marketable equity securities were included in net investment gain (loss). Unrealized gains and losses were recognized in accumulated other comprehensive income (loss), net of deferred taxes, on the balance sheet.

On January 1, 2018, we adopted ASU 2016-01, which requires us to measure all equity investments that do not result in consolidation and are not accounted for under the equity method at fair value, with any changes in fair value recognized in net investment gain (loss). Upon adoption, we reclassified $3.2 million of net unrealized gains related to marketable equity securities from accumulated other comprehensive income (loss) to opening retained earnings.

ASU 2016-01 also provides a measurement alternative for equity investments that do not have a readily determinable fair value in which investments can be recorded at cost less impairment, if any, adjusted for observable price changes for an identical or similar investment. We elected to record our equity investment that does not have a readily determinable fair value using the measurement alternative method. As of December 31, 2018, the Company had a note receivable of approximately $4.3 million, which was included in other receivables on the Consolidated Balance Sheets. During the three months ended March 31, 2019, this amount was repaid and reissued in the form of debt and equity. Approximately $3.4 million was issued as an equity investment, which represented a non-cash investing activity. The carrying value of this investment under the measurement alternative was $3.4 million as of December 31, 2019. The remaining amount, approximately $0.9 million, was converted into a new note receivable, which is included in other receivables on the Consolidated Balance Sheets and represents a non-cash operating activity.

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

As of December 31, 2019 and 2018, 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:

We have categorized our cash equivalents and our investments held at fair value into this hierarchy as follows:

	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	$	—

	Fair Value Measurements as of December 31, 2018 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	$	1,554	$	1,554	$	—	$	—
Available-for-sale debt securities
Corporate bonds		20,684		—		20,684		—
Municipal fixed-rate bonds		1,313		—		1,313		—
Asset-backed bonds		5,221		—		5,221		—
Mortgage/Agency-backed bonds		3,791		—		3,791		—
U.S. government bonds		9,206		9,206		—		—
Foreign government bonds		584		—		584		—
Marketable equity securities
Marketable equity securities – various industries		26,763		26,763		—		—
Equity in escrow		253		253		—		—
Deferred compensation plan assets		18,256		18,256		—		—
Total	$	87,625	$	56,032	$	31,593	$	—

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, security master files from 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.

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.