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 $16.8 million and $17.3 million at December 31, 2016 and 2015, respectively.

Available-for-Sale Investments

Available-for-sale investments at March 31, 2017 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	$	123,474	$	2,892	$	–	$	(1,675)	$	124,691
U.S. government agency mortgage-backed securities		27,908		1,070		(6)		(377)		28,595
Obligations of states and political subdivisions		159,417		9,466		(23)		(424)		168,436
Corporate securities		1,263,703		32,901		(5,731)		(13,837)		1,277,036
Mortgage-backed securities		26,577		515		–		(5)		27,087
Redeemable preferred stocks		13,789		168		–		(468)		13,489
Common stocks		15,732		8,728		(10)		(16)		24,434
	$	1,630,600	$	55,740	$	(5,770)	$	(16,802)	$	1,663,768

Available-for-sale investments at March 31, 2016 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	$	85,861	$	3,791	$	–	$	(193)	$	89,459
U.S. government agency mortgage-backed securities		21,845		1,596		(6)		(39)		23,396
Obligations of states and political subdivisions		166,725		10,660		(81)		(414)		176,890
Corporate securities		1,143,125		26,861		(8,013)		(28,181)		1,133,792
Mortgage-backed securities		24,991		475		–		(62)		25,404
Redeemable preferred stocks		17,977		556		–		(105)		18,428
Common stocks		15,983		7,822		(10)		(375)		23,420
	$	1,476,507	$	51,761	$	(8,110)	$	(29,369)	$	1,490,789

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 $190.2 million, $150.7 million and $109.1 million in fiscal 2017, 2016 and 2015, respectively. The gross realized gains on these sales totaled $5.1 million, $4.2 million and $4.6 million in fiscal 2017, 2016 and 2015, respectively. We realized gross losses on these sales of $2.2 million, $0.6 million and $0.7 million in fiscal 2017, 2016 and 2015, 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 2017, 2016 and 2015.

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 each 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 2017, 2016 or 2015.

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

		March 31, 2017				March 31, 2016
		Amortized Cost		Estimated Market Value		Amortized Cost		Estimated Market Value
		(In thousands)
Due in one year or less	$	35,399	$	35,795	$	48,679	$	49,146
Due after one year through five years		324,286		333,016		250,576		256,597
Due after five years through ten years		598,232		607,184		557,984		557,961
Due after ten years		616,585		622,763		560,317		559,833
		1,574,502		1,598,758		1,417,556		1,423,537

Mortgage backed securities		26,577		27,087		24,991		25,404
Redeemable preferred stocks		13,789		13,489		17,977		18,428
Equity securities		15,732		24,434		15,983		23,420
	$	1,630,600	$	1,663,768	$	1,476,507	$	1,490,789

Investments, other

The carrying value of other investments was as follows:

		March 31,
		2017		2016
		(In thousands)
Mortgage loans, net	$	262,875	$	217,198
Short-term investments		15,149		34,798
Real estate		66,174		34,416
Policy loans		17,112		17,091
Other equity investments		6,520		8,318
	$	367,830	$	311,821

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 4.3% to 6.9% with maturities between 2017 and 2036. The allowance for probable losses was $0.5 million and $0.4 million as of March 31, 2017 and 2016, respectively. The estimated fair value of these loans as of March 31, 2017 and 2016 approximated the carrying value. These loans represent first lien mortgages held by us.

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 obtained through foreclosure and held for sale is carried at the lower of fair value at time of foreclosure 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.