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

We deposit bonds with insurance regulatory authorities to meet statutory requirements. The adjusted cost of bonds on deposit with insurance regulatory authorities was $30.8 million and $32.4 million as of December 31, 2018 and 2017, respectively.

Available-for-Sale Investments

Available-for-sale investments as of March 31, 2019 were as follows:

		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses More than 12 Months		Gross Unrealized Losses Less than 12 Months		Estimated Market Value

		(In thousands)
U.S. treasury securities and government obligations	$	136,010	$	2,409	$	(2,104)	$	(447)	$	135,868
U.S. government agency mortgage-backed securities		31,101		433		(146)		(19)		31,369
Obligations of states and political subdivisions		298,955		8,079		(233)		(905)		305,896
Corporate securities		1,613,199		14,777		(14,257)		(24,986)		1,588,733
Mortgage-backed securities		148,203		880		(285)		(903)		147,895
Redeemable preferred stocks		1,493		20		–		(45)		1,468
	$	2,228,961	$	26,598	$	(17,025)	$	(27,305)	$	2,211,229

Available-for-sale investments as of March 31, 2018 were as follows:

		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses More than 12 Months		Gross Unrealized Losses Less than 12 Months		Estimated Market Value

		(In thousands)
U.S. treasury securities and government obligations	$	123,557	$	3,595	$	(1,036)	$	(203)	$	125,913
U.S. government agency mortgage-backed securities		15,941		572		–		(93)		16,420
Obligations of states and political subdivisions		178,702		9,938		(217)		(18)		188,405
Corporate securities		1,388,300		50,056		(3,009)		(1,826)		1,433,521
Mortgage-backed securities		114,581		2,451		(1)		(153)		116,878
Redeemable preferred stocks		2,118		129		–		–		2,247
	$	1,823,199	$	66,741	$	(4,263)	$	(2,293)	$	1,883,384

The available-for-sale tables include gross unrealized losses that are not deemed to be other-than-temporarily impaired, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position.

We sold available-for-sale securities with a fair value of $114.8 million, $163.7 million and $190.2 million in fiscal 2019, 2018 and 2017, respectively. The gross realized gains on these sales totaled $2.0 million, $5.4 million and $5.1 million in fiscal 2019, 2018 and 2017, respectively. We realized gross losses on these sales of $0.2 million, $0.3 million and $2.2 million in fiscal 2019, 2018 and 2017, respectively.

The unrealized losses of more than twelve months in the available-for-sale tables are considered temporary declines. We track each investment with an unrealized loss and evaluate them on an individual basis for other-than-temporary impairments, including obtaining corroborating opinions from third party sources, performing trend analysis and reviewing management’s future plans. Certain of these investments may have declines determined by management to be other-than-temporary and we recognized these write-downs through earnings. There were no write downs in fiscal 2019, 2018 and 2017.

The investment portfolio primarily consists of corporate securities and U.S. government securities. We believe we monitor our investments as appropriate. Our methodology of assessing other-than-temporary impairments is based on security-specific analysis as of the balance sheet date and considers various factors, including the length of time to maturity, the extent to which the fair value has been less than the cost, the financial condition and the near-term prospects of the issuer, and whether the debtor is current on its contractually obligated interest and principal payments. Nothing has come to management’s attention that would lead to the belief that any issuer would not have the ability to meet the remaining contractual obligations of the security, including payment at maturity. We have the ability and intent not to sell our fixed maturity and common stock investments for a period of time sufficient to allow us to recover our costs.

The portion of other-than-temporary impairment related to a credit loss is recognized in earnings. The significant inputs utilized in the evaluation of mortgage backed securities credit losses include ratings, delinquency rates, and prepayment activity. The significant inputs utilized in the evaluation of asset backed securities credit losses include the time frame for principal recovery and the subordination and value of the underlying collateral.

There were no credit losses recognized in earnings for which a portion of an other-than-temporary impairment was recognized in accumulated other comprehensive loss for fiscal 2019, 2018 or 2017.

The adjusted cost and estimated market value of available-for-sale investments by contractual maturity, were as follows:

		March 31, 2019				March 31, 2018
		Amortized Cost		Estimated Market Value		Amortized Cost		Estimated Market Value
		(In thousands)
Due in one year or less	$	71,987	$	71,954	$	36,446	$	36,674
Due after one year through five years		541,195		540,658		441,159		450,749
Due after five years through ten years		621,031		614,485		607,075		625,282
Due after ten years		845,052		834,769		621,820		651,554
		2,079,265		2,061,866		1,706,500		1,764,259

Mortgage backed securities		148,203		147,895		114,581		116,878
Redeemable preferred stocks		1,493		1,468		2,118		2,247
	$	2,228,961	$	2,211,229	$	1,823,199	$	1,883,384

As of March 31, 2018, equity investments were classified as available-for-sale on our balance sheet. However, upon adoption of ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities, on April 1, 2018, the updated guidance eliminated the available-for-sale balance sheet classification for equity investments. As of March 31, 2019 and 2018, our common stock and non-redeemable preferred stock that are included in Investments, fixed maturities and marketable equities on our balance sheet are stated in the table below. The changes in the fair value of these equity investments are recognized through Net investment and interest income.

Equity investments of common stock and non-redeemable preferred stock were as follows:

		March 31, 2019				March 31, 2018
		Amortized Cost		Estimated Market Value		Amortized Cost		Estimated Market Value
		(In thousands)

Common stocks	$	10,123	$	17,379	$	15,732	$	27,862
Non-redeemable preferred stocks		7,451		6,789		8,491		8,614
	$	17,574	$	24,168	$	24,223	$	36,476

Investments, other

The carrying value of other investments was as follows:

		March 31,
		2019		2018
		(In thousands)
Mortgage loans, net	$	225,829	$	309,952
Short-term investments		5,546		10,350
Real estate		53,519		53,776
Policy loans		10,491		17,677
Other equity investments		5,351		7,309
	$	300,736	$	399,064

Mortgage loans are carried at the unpaid balance, less an allowance for probable losses net of any unamortized premium or discount. The portfolio of mortgage loans is principally collateralized by self-storage facilities and commercial properties. The interest rate range on the mortgage loans is 4.1% to 8.2% with maturities between 2019 and 2036. The allowance for probable losses was $0.5 million and $0.5 million as of March 31, 2019 and 2018, respectively. The estimated fair value of these loans as of March 31, 2019 and 2018 approximated the carrying value. These loans represent first lien mortgages held by us. Mortgage loans are reviewed on an ongoing basis and analysis may include market analysis, estimated valuations of the underlying collateral, loan to value ratios, tenant creditworthiness and other factors. For our mortgage loans, no specifically identified loans were impaired as of March 31, 2019. We have not experienced any material losses related to the notes from individual or groups of notes in any particular industry or geographic area.

Short-term investments consist primarily of investments in money market funds, mutual funds and any other investments with short-term characteristics that have original maturities of less than one year at acquisition. These investments are recorded at cost, which approximates fair value.

Real estate held for investment is carried at the lower of fair value at time of acquisition or current estimated fair value less cost to sell. Other equity investments are carried at cost and assessed for impairment.

Insurance policy loans are carried at their unpaid balance.