We discuss regulatory matters in Note 4 of the Notes to Consolidated Financial Statements in the Annual Report and provide updates to those discussions and information about new regulatory matters below. With the exception of regulatory balancing accounts, we generally do not earn a return on our regulatory assets until such time as a related cash expenditure has been made. Upon the occurrence of a cash expenditure associated with a regulatory asset, the related amounts are recoverable through a regulatory account mechanism for which we earn a return authorized by applicable regulators, which generally approximates the three-month commercial paper rate. The periods during which we recognize a regulatory asset while we do not earn a return vary by regulatory asset.


REGULATORY ASSETS (LIABILITIES)
(Dollars in millions)
	Sempra				SDG&E				SoCalGas
	March 31, 2024		December 31, 2023		March 31, 2024		December 31, 2023		March 31, 2024		December 31, 2023

Fixed-price contracts and other derivatives	$	50	$	215	$	26	$	14	$	24	$	201
Deferred income taxes recoverable in rates	1,327		1,142		668		626		573		430
Pension and PBOP plan obligations	(194)		(212)		58		48		(252)		(260)
Employee benefit costs	24		24		3		3		21		21
Removal obligations	(3,156)		(3,082)		(2,534)		(2,468)		(622)		(614)
Environmental costs	148		139		115		105		33		34
Sunrise Powerlink fire mitigation	125		124		125		124		—		—
Regulatory balancing accounts(1)(2):
Commodity – electric	(180)		(233)		(180)		(233)		—		—
Commodity – gas, including transportation	(280)		(259)		42		52		(322)		(311)
Safety and reliability	1,044		959		221		207		823		752
Public purpose programs	(361)		(273)		(162)		(144)		(199)		(129)
Wildfire mitigation plan	735		685		735		685		—		—
Liability insurance premium	110		113		86		90		24		23
Other balancing accounts	(112)		373		(282)		(152)		170		525
Other regulatory (liabilities) assets, net(2)	(85)		(10)		27		49		(110)		(58)
Total	$	(805)	$	(295)	$	(1,052)	$	(994)	$	163	$	614

(1) At March 31, 2024 and December 31, 2023, the noncurrent portion of regulatory balancing accounts – net undercollected for Sempra was $1,903 and $1,913, respectively, for SDG&E was $827 and $950, respectively, and for SoCalGas was $1,076 and $963, respectively.

In May 2022, SDG&E and SoCalGas filed their 2024 GRC applications requesting CPUC approval of test year revenue requirements for 2024 and attrition year adjustments for 2025 through 2027. SDG&E and SoCalGas requested revenue requirements for 2024 of $3.0 billion and $4.4 billion, respectively. SDG&E and SoCalGas proposed post-test year revenue requirement changes using various mechanisms that are estimated to result in annual increases of approximately 8% to 11% at SDG&E and approximately 6% to 8% at SoCalGas. Intervening parties have proposed various adjustments to SDG&E’s and SoCalGas’ revenue requirement requests. In October 2022, the CPUC issued a scoping ruling that set a schedule for the proceeding, including the expected issuance of a proposed decision in the second quarter of 2024. The CPUC has authorized SDG&E and SoCalGas to recognize the effects of the 2024 GRC final decision retroactive to January 1, 2024.

In October 2023, SDG&E submitted a separate request to the CPUC in its 2024 GRC describing $2.2 billion in costs to implement its wildfire mitigation plans from 2019 through 2022, and seeking review and recovery of the incremental wildfire mitigation plan costs incurred during that period, totaling $1.5 billion. SDG&E expects to receive a proposed decision on this request in late 2024. In February 2024, the CPUC approved an interim cost recovery mechanism that would permit SDG&E to recover in rates $194 million of its wildfire mitigation plan regulatory account balance in 2024 and, if a recovery mechanism is not in place by January 1, 2025, an additional $96 million in 2025. Such recovery of SDG&E’s wildfire mitigation plan regulatory account balance will be subject to reasonableness review by the CPUC. SDG&E also expects to submit a separate request for review and recovery of its 2023 wildfire mitigation plan costs in late 2024.

SDG&E and SoCalGas recorded CPUC-authorized revenues in the three months ended March 31, 2024 based on 2023 levels authorized under the 2019 GRC because a final decision in the 2024 GRC remains pending. The results of the 2024 GRC may materially differ from what is contained in the GRC applications.

The CPUC approved the following cost of capital for SDG&E and SoCalGas that became effective on January 1, 2023 and was to remain in effect through December 31, 2025, subject to the CCM. The CPUC has issued a ruling to initiate a second phase of this cost of capital proceeding to evaluate potential modifications to the CCM. We expect a proposed decision on the second phase in the second half of 2024.


AUTHORIZED COST OF CAPITAL FOR 2023

SDG&E							SoCalGas
Authorized weighting		Return on rate base		Weighted return on rate base(1)			Authorized weighting		Return on rate base		Weighted return on rate base
45.25	%	4.05	%	1.83	%	Long-Term Debt	45.60	%	4.07	%	1.86	%
2.75		6.22		0.17		Preferred Equity	2.40		6.00		0.14
52.00		9.95		5.17		Common Equity	52.00		9.80		5.10
100.00	%			7.18	%		100.00	%			7.10	%

The CCM was triggered for SDG&E and SoCalGas on September 30, 2023. In December 2023, the CPUC approved increases to SDG&E’s and SoCalGas’ authorized rates of return effective January 1, 2024, which are in effect through December 31, 2025, subject to the CCM. In January 2024, several parties submitted a request for the CPUC to review such approval. In March 2024, the CPUC issued a proposed decision denying the intervenor petition seeking to suspend the CCM and its resulting changes that became effective on January 1, 2024. We expect a final decision in the second quarter of 2024.


AUTHORIZED COST OF CAPITAL FOR 2024 – 2025

SDG&E							SoCalGas
Authorized weighting		Return on rate base		Weighted return on rate base			Authorized weighting		Return on rate base		Weighted return on rate base
45.25	%	4.34	%	1.96	%	Long-Term Debt	45.60	%	4.54	%	2.07	%
2.75		6.22		0.17		Preferred Equity	2.40		6.00		0.14
52.00		10.65		5.54		Common Equity	52.00		10.50		5.46
100.00	%			7.67	%		100.00	%			7.67	%

SDG&E files separately with the FERC for its authorized ROE on FERC-regulated electric transmission operations and assets. SDG&E’s currently effective TO5 settlement provides for a ROE of 10.60%, consisting of a base ROE of 10.10% plus an additional 50 bps for participation in the California ISO (the California ISO adder). If the FERC issues an order ruling that California IOUs are no longer eligible for the California ISO adder, SDG&E would refund the California ISO adder as of the refund effective date (June 1, 2019) or such other date set by the FERC if such a refund is determined to be required by the terms of the TO5 settlement. The TO5 settlement will remain in effect until terminated by a notice provided at least six months before the end of the calendar year. Following any such notice, SDG&E would file an updated rate request with an effective date of January 1 of the following year.

We provide below updates to ongoing matters related to SONGS, a nuclear generating facility near San Clemente, California that permanently ceased operations in June 2013, and in which SDG&E has a 20% ownership interest. We discuss SONGS further in Note 15 of the Notes to Consolidated Financial Statements in the Annual Report.

As a result of Edison’s decision to permanently retire SONGS Units 2 and 3, Edison began the decommissioning phase of the plant. Major decommissioning work began in 2020. We expect the majority of the decommissioning work to be completed around 2030. Decommissioning of Unit 1, removed from service in 1992, is largely complete. The remaining work for Unit 1 will be completed once Units 2 and 3 are dismantled and the spent fuel is removed from the site. The spent fuel is currently being stored on-site, until the DOE identifies a spent fuel storage facility and puts in place a program for the fuel’s disposal. SDG&E is responsible for approximately 20% of the total decommissioning cost.

In accordance with state and federal requirements and regulations, SDG&E has assets held in the NDT to fund its share of decommissioning costs for SONGS Units 1, 2 and 3. Amounts that were collected in rates for SONGS’ decommissioning are invested in the NDT, which is comprised of externally managed trust funds. Amounts held by the NDT are invested in accordance with CPUC regulations. SDG&E classifies debt and equity securities held in the NDT as available-for-sale. The NDT assets are presented on the Sempra and SDG&E Condensed Consolidated Balance Sheets at fair value with the offsetting credits recorded in noncurrent Regulatory Liabilities.

Except for the use of funds for the planning of decommissioning activities or NDT administrative costs, CPUC approval is required for SDG&E to access the NDT assets to fund SONGS decommissioning costs for Units 2 and 3. In December 2023, the CPUC granted SDG&E authorization to access NDT funds of up to $79 million for forecasted 2024 costs.

The following table shows the fair values and gross unrealized gains and losses for the securities held in the NDT on the Sempra and SDG&E Condensed Consolidated Balance Sheets. We provide additional fair value disclosures for the NDT in Note 8.


NUCLEAR DECOMMISSIONING TRUSTS
(Dollars in millions)
	Cost		Gross unrealized gains		Gross unrealized losses		Estimated fair value
	March 31, 2024
Short-term investments, primarily cash equivalents	$	28	$	—	$	—	$	28
Equity securities	89		239		(3)		325
Debt securities:
Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies(1)	59		1		(1)		59
Municipal bonds(2)	277		2		(9)		270
Other securities(3)	231		1		(10)		222
Total debt securities	567		4		(20)		551
Receivables (payables), net	(18)		—		—		(18)
Total	$	666	$	243	$	(23)	$	886

	December 31, 2023
Short-term investments, primarily cash equivalents	$	21	$	—	$	—	$	21
Equity securities	89		225		(2)		312
Debt securities:
Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	50		2		(1)		51
Municipal bonds	280		3		(8)		275
Other securities	228		3		(11)		220
Total debt securities	558		8		(20)		546
Receivables (payables), net	(7)		—		—		(7)
Total	$	661	$	233	$	(22)	$	872

Net unrealized gains and losses, as well as realized gains and losses that are reinvested in the NDT, are included in noncurrent Regulatory Liabilities on Sempra’s and SDG&E’s Condensed Consolidated Balance Sheets. We determine the cost of securities in the trusts on the basis of specific identification.

The present value of SDG&E’s asset retirement obligation related to decommissioning costs for all three SONGS units was $497 million at March 31, 2024 and is based on a cost study prepared in 2020 that is pending CPUC approval. SDG&E expects to receive a proposed decision in the third quarter of 2024.

SDG&E and the other owners of SONGS have insurance to cover claims from nuclear liability incidents arising at SONGS. Currently, this insurance provides $500 million in coverage limits, the maximum amount available, including coverage for acts of terrorism. In addition, the Price-Anderson Act provides an additional $1.5 billion of coverage. If a nuclear liability loss occurs at SONGS and exceeds the $500 million insurance limit, this additional coverage would be available to provide a total of $2.0 billion in coverage limits per incident.

The SONGS owners have nuclear property damage insurance of $130 million, which exceeds the minimum federal requirement of $50 million. This insurance coverage is provided through NEIL. The NEIL policies have specific exclusions and limitations that can result in reduced coverage. Insured members as a group are subject to retrospective premium assessments to cover losses sustained by NEIL under all issued policies. SDG&E could be assessed up to $2 million of retrospective premiums based on overall member claims.

The nuclear property insurance program includes an industry aggregate loss limit for non-certified acts of terrorism (as defined by the Terrorism Risk Insurance Act) of $3.24 billion. This is the maximum amount that will be paid to insured members who suffer losses or damages from these non-certified terrorist acts.