Future decommissioning costs related to SCE's nuclear assets are expected to be funded from independent decommissioning trusts.

The following table sets forth amortized cost and fair value of the trust investments (see Note 4 for a discussion of fair value of the trust investments):

Short-term investments included $18 million and $41 million of repurchase agreements payable by financial institutions which earn interest, were fully and 97% secured by U.S. Treasury securities and mature by April 3, 2023 and January 3, 2023 as of March 31, 2023 and December 31, 2022, respectively.

Trust fund earnings (based on specific identification) increase the trust fund balance and the asset retirement obligation ("ARO") regulatory liability. Unrealized holding gains, net of losses, were $1.7 billion and $1.6 billion at March 31, 2023 and December 31, 2022, respectively.

Trust assets are used to pay income taxes arising from trust investing activity. Deferred tax liabilities related to net unrealized gains were $359 million and $321 million at March 31, 2023 and December 31, 2022, respectively. Accordingly, the fair value of trust assets available to pay future decommissioning costs, net of deferred income taxes, totaled $3.7 billion and $3.6 billion at March 31, 2023 and December 31, 2022, respectively.

The following table summarizes the gains and losses for the trust investments:

Due to regulatory mechanisms, changes in assets of the trusts from income or loss items do not materially affect earnings.

Edison International Parent and Other's Investments

Edison International Parent and Other hold strategic investments in companies focused on developing electric technologies and services. As of March 31, 2023 and December 31, 2022, these investments consist of $2 million and $5 million of marketable securities, respectively, and $12 million of equity investments without readily determinable fair values (included as "Other investments" on Edison International's consolidated balance sheets) at both dates. For further information of fair value of marketable securities, see Note 4. The equity investments without readily determinable fair values balances included cumulative upward adjustments of $9 million at both March 31, 2023 and December 31, 2022. The cumulative upward adjustments resulted primarily from values determined by additional capital infusions.

The following table summarizes unrealized gains/(losses) for equity investments held at the reporting date, recorded as "Other income" on Edison International's consolidated statements of income:


	Three months ended March 31,
(in millions)	2023		2022
Marketable securities	$	(3)	$	(2)

Three months ended March 31,

(in millions)

Gross realized gains

Gross realized losses

Net unrealized gains/(losses) for equity securities