SOUTHERN CO

(B)REGULATORY MATTERS

See Note 2 to the financial statements in Item 8 of the Form 10-K for additional information relating to regulatory matters.

The fuel and natural gas cost recovery balances for the traditional electric operating companies and Southern Company Gas, respectively, at March 31, 2025 and December 31, 2024 were as follows:

(*)Mississippi Power also has wholesale MRA and Market Based (MB) fuel cost recovery factors. At March 31, 2025 and December 31, 2024, wholesale MRA fuel costs were over recovered $13 million and $19 million, respectively, and were included in other current liabilities on Mississippi Power's balance sheets. The wholesale MB fuel cost recovery wasimmaterial for both periods presented.

Nuclear Construction

Georgia Power placed Plant Vogtle Units 3 and 4 in service on July 31, 2023 and April 29, 2024, respectively. Georgia Power's net capital costs incurred through March 31, 2025 in connection with Plant Vogtle Units 3 and 4, and its approximate proportionate share of remaining capital costs to be incurred after March 31, 2025, including completion of site demobilization and remaining contractor obligations, is as follows:

(a)Includes approximately $1.2 billion of costs that are not shared with the other Vogtle Owners. Excludes financing costs capitalized through AFUDC of approximately $440 million accrued through Unit 4's in-service date.

(b)Net of $1.7 billion received from Toshiba under the Guarantee Settlement Agreement and approximately $188 million in related customer refunds.

Other Construction

At March 31, 2025, Georgia Power had recorded approximately $963 million of combined capital costs, excluding AFUDC, for the projects reflected in the table below. The total certified amounts related to these projects are approximately $2.8 billion, excluding AFUDC. The ultimate outcome of these matters cannot be determined at this time.

Performance Evaluation Plan

On March 17, 2025, Mississippi Power submitted its annual retail PEP filing for 2025 to the Mississippi PSC, which requested a 4.0%, or $41 million, annual increase in revenues, primarily due to increases in investment and depreciation. In accordance with the PEP rate schedule, an increase of 2.0% of total retail revenues, or approximately $22 million, became effective with the first billing cycle of April 2025, subject to refund. The related proceedings are projected to conclude in summer 2025. The ultimate outcome of this matter cannot be determined at this time.

Environmental Compliance Overview Plan

On April 1, 2025, the Mississippi PSC approved Mississippi Power's annual ECO Plan filing for 2025, resulting in a $6 million annual increase in revenues effective with the first billing cycle of May 2025.

System Restoration Rider

On March 3, 2025, Mississippi Power submitted its annual SRR filing for 2025 to the Mississippi PSC, indicating no change in retail rates. The filing includes a request to increase the minimum annual SRR accrual from $12.6 million to $13.2 million. The ultimate outcome of this matter cannot be determined at this time.

Plant Daniel

In November 2024, Mississippi Power entered into an agreement with FP&L to acquire FP&L's 50% ownership interest in Plant Daniel Units 1 and 2. This acquisition will include a payment by FP&L to Mississippi Power of between $35 million and $37 million, which represents an estimate of the incremental cost to Mississippi Power to assume ownership of FP&L's interest, based on the timing of the completion of the transaction. On January 7, 2025, the Mississippi PSC approved Mississippi Power's request for (i) the inclusion of the acquired assets and the associated costs at Plant Daniel in Mississippi Power's retail rate base, upon completion of the transaction, (ii) the establishment of a new regulatory liability account in which all of the proceeds to be paid by FP&L will be recorded, and (iii) Mississippi Power's ability to amortize that regulatory liability by charging certain expenditures against it. On April 21, 2025, the Florida PSC preliminarily approved the transaction. Interested parties may file an objection or protest by May 12, 2025. In the absence of such a filing, the approval will become final and effective upon the issuance of a final order by the Florida PSC. The completion of the transaction is subject to the satisfaction or waiver of certain conditions, including, among other customary closing conditions, a final order from the Florida PSC. The ultimate outcome of this matter cannot be determined at this time.

Municipal and Rural Associations Tariff

On April 3, 2025, the FERC approved a settlement agreement filed by Mississippi Power and Cooperative Energy in December 2024. The settlement agreement provides for (i) a $1 million increase in annual wholesale base revenues and a refund to customers of approximately $4 million, (ii) a rate escalation of 2.5% on an annual basis in periods subsequent to December 31, 2024 and continuing through the end of the shared service agreement on December 31, 2035, and (iii) a waiver of rights by Mississippi Power and Cooperative Energy to file for any changes in non-fuel rates through the end of the term of the shared service agreement.

Infrastructure Replacement Programs and Capital Projects

On March 26, 2025, the Illinois Supreme Court denied Nicor Gas' petition for leave to appeal $14 million of the 2019 Qualifying Infrastructure Plant disallowance. This matter is now concluded and had no impact on the current period financial statements.