We have investments in debt and equity securities held in nuclear decommissioning trust, coal reclamation escrow account, and an active union employee medical account. Investments in debt securities are classified as available-for-sale securities. We record both debt and equity security investments at their fair value on our Condensed Consolidated Balance Sheets. See Note 11 for a discussion of how fair value is determined and the classification of the investments within the fair value hierarchy. The investments in each trust or account are restricted for use and are intended to fund specified costs and activities as further described for each fund below.

Nuclear Decommissioning Trust - To fund the future costs APS expects to incur to decommission Palo Verde, APS established an external decommissioning trust in accordance with NRC regulations. Third-party investment managers are authorized to buy and sell securities per stated investment guidelines. The trust funds are invested in fixed income securities and equity securities. Earnings and proceeds from sales and maturities of securities are reinvested in the trust. Because of the ability of APS to recover decommissioning

costs in rates, and in accordance with the regulatory treatment, APS has deferred realized and unrealized gains and losses (including other-than-temporary impairments) in other regulatory liabilities.

Coal Reclamation Escrow Account - APS has investments restricted for the future coal mine reclamation funding related to Four Corners. This escrow account is primarily invested in fixed income securities. Earnings and proceeds from sales of securities are reinvested in the escrow account. Because of the ability of APS to recover coal reclamation costs in rates, and in accordance with the regulatory treatment, APS has deferred realized and unrealized gains and losses (including other-than-temporary impairments) in other regulatory liabilities. Activities relating to APS coal reclamation escrow account investments are included within the other special use funds in the table below.

Active Union Employee Medical Account - APS has investments restricted for paying active union employee medical costs. These investments were transferred from APS other postretirement benefit trust assets into the active union employee medical trust in January 2018 (see Note 7 in the 2018 Form 10-K). These investments may be used to pay active union employee medical costs incurred in the current and future periods. The account is invested primarily in fixed income securities. In accordance with the ratemaking treatment, APS has deferred the unrealized gains and losses (including other-than-temporary impairments) in other regulatory assets. Activities relating to active union employee medical account investments are included within the other special use funds in the table below.

The following tables present the unrealized gains and losses based on the original cost of the investment and summarizes the fair value of APS's nuclear decommissioning trust and other special use fund assets at June 30, 2019 and December 31, 2018 (dollars in thousands):



	June 30, 2019
	Fair Value							Total Unrealized Gains		Total Unrealized Losses
Investment Type:	Nuclear Decommissioning Trust		Other Special Use Funds		Total			Total Unrealized Gains		Total Unrealized Losses
Equity securities	$	474,694	$	13,200	$	487,894		$	291,295	$	—
Available for sale-fixed income securities	469,089		227,361		696,450		(a)	24,638		(696		)
Other	6,665		997		7,662		(b)	—		—
Total	$	950,448	$	241,558	$	1,192,006		$	315,933	$	(696	)



	December 31, 2018
	Fair Value							Total Unrealized Gains		Total Unrealized Losses
Investment Type:	Nuclear Decommissioning Trust		Other Special Use Funds		Total			Total Unrealized Gains		Total Unrealized Losses
Equity securities	$	402,008	$	45,130	$	447,138		$	222,147	$	(459	)
Available for sale-fixed income securities	446,978		190,378		637,356		(a)	8,634		(6,778		)
Other	2,148		593		2,741		(b)	—		—
Total	$	851,134	$	236,101	$	1,087,235		$	230,781	$	(7,237	)

The following table sets forth APS's realized gains and losses relating to the sale and maturity of available-for-sale debt securities and equity securities, and the proceeds from the sale and maturity of these investment securities for the three and six months ended June 30, 2019 and 2018 (dollars in thousands):



	Three Months Ended June 30,
	Nuclear Decommissioning Trust			Other Special Use Funds		Total
2019
Realized gains	$	2,643		$	—	$	2,643
Realized losses	(1,700		)	—		(1,700		)
Proceeds from the sale of securities (a)	93,559			36,747		130,306
2018
Realized gains	$	1,484		$	—	$	1,484
Realized losses	(2,978		)	—		(2,978		)
Proceeds from the sale of securities (a)	122,790			2,426		125,216



	Six Months Ended June 30,
	Nuclear Decommissioning Trust			Other Special Use Funds		Total
2019
Realized gains	$	3,746		$	—	$	3,746
Realized losses	(3,105		)	—		(3,105		)
Proceeds from the sale of securities (a)	216,152			93,202		309,354
2018
Realized gains	$	2,298		$	1	$	2,299
Realized losses	(5,025		)	—		(5,025		)
Proceeds from the sale of securities (a)	253,246			4,981		258,227



	Nuclear Decommissioning Trust (a)		Coal Reclamation Escrow Account		Active Union Medical Trust		Total
Less than one year	$	37,373	$	22,253	$	40,219	$	99,845
1 year – 5 years	126,745		17,449		140,569		284,763
5 years – 10 years	113,989		1,807		—		115,796
Greater than 10 years	190,982		5,064		—		196,046
Total	$	469,089	$	46,573	$	180,788	$	696,450

Includes certain fixed income investments that are not due at a single maturity date. These investments have been allocated within the table based on the final payment date of the instrument.