SO Form 3: Comptroller Matthew Kim discloses RSUs and 11,812.97 total holdings

Rhea-AI Filing Summary

Matthew M. Kim, who is listed as an officer (Comptroller) and director of The Southern Company (SO), filed an initial Form 3 reporting his beneficial ownership in Southern Company securities.

He directly owns 9,009 shares of Southern Company common stock and indirectly holds 2,803.97 shares through a 401(k). The filing also discloses derivative/award-based holdings: Restricted Stock Units and Phantom Stock Units totaling 2,153.75 underlying shares (635; 308; 366.75; 844) with specified vesting schedules, including grants from 2023, 2024 and 2025.

Insights

Financial Analyst

TL;DR: Routine Section 16 initial disclosure showing direct, indirect and award-based holdings by a named officer.

The Form 3 is a standard initial beneficial ownership filing. It reports 9,009 directly held shares and 2,803.97 indirect shares in a 401(k), plus 2,153.75 units from restricted and phantom stock awards with multi-year vesting. These awards have specified grant dates and staggered vesting, which clarifies future share settlement timing but does not by itself change current outstanding shares.

Corporate Governance Expert

TL;DR: Disclosure aligns with Section 16 requirements and clarifies officer compensation structure via equity awards.

The filing identifies the reporting person as Comptroller and includes detailed award explanations: RSUs from 2023, 2024 and 2025 with one‑third annual vesting patterns and phantom units acquired under a deferred compensation plan. The information is material for governance transparency because it shows the timing and form of equity-based compensation for a senior officer.

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person^*

Kim Matthew M.

(Last) (First) (Middle)

30 IVAN ALLEN JR. BLVD., NW

(Street)

ATLANTA GA 30308

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
07/31/2025

3. Issuer Name and Ticker or Trading Symbol
SOUTHERN CO [ SO ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Comptroller

5. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Southern Company Common Stock	9,009	D
Southern Company Common Stock	2,803.97	I	401(k)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Southern Co Restricted Stock Units(1)	(1)	(1)	Southern Company Common Stock	635	$0	D
Southern Co Restricted Stock Units(2)	(2)	(2)	Southern Company Common Stock	308	$0	D
Phantom Stock Units(3)	(3)	(3)	Southern Company Common Stock	366.75	$0	D
Southern Co Restricted Stock Units(4)	(4)	(4)	Southern Company Common Stock	844	$0	D

Explanation of Responses:

1. Represents Restricted Stock Units granted on January 31, 2024. The award vested 1/3 on the first anniversary of the grant date. The remaining award will vest 1/3 in 2026 and 1/3 in 2027. Each restricted stock unit represents the right to receive, at settlement, one share of common stock.

2. Represents Restricted Stock Units granted on February 1, 2023. The award vested 1/3 on each of the first and second anniversaries of the grant date. The remaining award will vest in 2026. Each restricted stock unit represents the right to receive, at settlement, one share of common stock.

3. Acquired on various dates between January 5, 2018 and March 1, 2024 pursuant to the Southern Company Deferred Compensation Plan, at prices ranging from $43.28 to $79.52 per unit, and the dividend reinvestment feature of the plan payable in cash only upon termination.

4. Represents Restricted Stock Units granted on February 5, 2025. The award will vest 1/3 per year on the first, second and third anniversaries of grant date. Each restricted stock unit represents the right to receive, at settlement, one share of common stock.

	/s/ Brittney Anderson, Attorney-in-Fact for Matthew M. Kim	08/22/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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