Southern Co (SO) comptroller vests RSUs and withholds shares for tax obligations

Rhea-AI Filing Summary

Southern Company comptroller Matthew M. Kim reported routine equity compensation activity involving restricted stock units that converted into common shares. On April 1, 2026, he exercised several Southern Company and performance restricted stock unit awards into common stock, reflecting scheduled vesting under prior grants.

In connection with these awards, 82 shares of Southern Company common stock were delivered back to the company at $96.94 per share to cover FICA withholding obligations because he is retirement-eligible under the stock grant documents. After these transactions, Kim directly held 6,888 shares of Southern Company common stock.

Insider Trade Summary

78 shares exercised/converted

Mixed 5 txns

Insider Kim Matthew M.

Role Comptroller

Type	Security	Shares	Price	Value
Exercise	Southern Co Restricted Stock Units	13	$0.00	--
Exercise	Southern Co Restricted Stock Units	23	$0.00	--
Exercise	Performance Restricted Stock Units	42	$0.00	--
Exercise	Southern Company Common Stock	82	$0.00	--
Tax Withholding	Southern Company Common Stock	82	$96.94	$8K

Holdings After Transaction: Southern Co Restricted Stock Units — 305 shares (Direct); Performance Restricted Stock Units — 975 shares (Direct); Southern Company Common Stock — 6,970 shares (Direct)

Footnotes (1)

1. Represents shares delivered to the Company to cover FICA withholding obligations due because Reporting Person is retirement eligible pursuant to his applicable stock grant documents. Includes 4 accrued dividend equivalent units. Represents shares delivered to the Company to cover FICA withholding obligations due because Reporting Person is retirement eligible pursuant to his applicable stock grant documents. Represents restricted stock units granted on January 31, 2024, payable in Southern Company common stock and will continue to vest on the third anniversary of the grant date. Additional units will be acquired with deemed dividends. Shares will be withheld upon vesting to satisfy income tax requirements. Represents restricted stock units granted on February 5, 2025, payable in Southern Company common stock and will continue to vest on the remaining second and third anniversary of the grant date. Additional units will be acquired with deemed dividends. Shares will be withheld upon vesting to satisfy income tax requirements. Represents restricted stock units granted on February 11, 2026, payable in Southern Company common stock and vest every year on the first, second and third anniversary of the grant date. Additional units will be acquired with deemed dividends. Shares will be withheld upon vesting to satisfy income tax requirements.

Key Figures

Tax-withholding shares: 82 shares Tax-withholding price: $96.94 per share RSU exercises: 78 shares +4 more

7 metrics

Tax-withholding shares 82 shares Shares delivered to company to cover FICA withholding

Tax-withholding price $96.94 per share Value applied to 82 shares delivered for FICA obligations

RSU exercises 78 shares Underlying Southern Company common stock from derivative exercises

Post-transaction holdings 6,888 shares Southern Company common stock held directly after transactions

RSU transaction 1 13 units Southern Co Restricted Stock Units exercised into common stock

RSU transaction 2 23 units Southern Co Restricted Stock Units exercised into common stock

Performance RSUs 42 units Performance Restricted Stock Units exercised into common stock

Key Terms

Restricted Stock Units, Performance Restricted Stock Units, FICA withholding obligations, dividend equivalent units, +1 more

5 terms

Restricted Stock Units financial

"Represents restricted stock units granted on January 31, 2024, payable in Southern Company common stock"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

Performance Restricted Stock Units financial

"security_title": "Performance Restricted Stock Units""

Performance restricted stock units (PRSUs) are promises to deliver company shares to employees or executives only if the business meets specific performance targets and any time-based holding rules. Think of them as a bonus that converts into stock only after set goals are reached, so investors watch PRSUs for two reasons: they can dilute existing shares if paid out, and they signal how closely management’s pay is tied to company performance.

FICA withholding obligations financial

"Represents shares delivered to the Company to cover FICA withholding obligations due because Reporting Person is retirement eligible"

dividend equivalent units financial

"Includes 4 accrued dividend equivalent units."

retirement eligible financial

"due because Reporting Person is retirement eligible pursuant to his applicable stock grant documents"

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

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

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Kim Matthew M.

(Last) (First) (Middle)

30 IVAN ALLEN JR. BLVD., NW

(Street)

ATLANTA GEORGIA 30308

(City) (State) (Zip)

UNITED STATES

(Country)

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

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/01/2026

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

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

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

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Southern Company Common Stock	04/01/2026		M		82(1)	A	$0	6,970	D
Southern Company Common Stock	04/01/2026		F		82(2)	D	$96.94	6,888	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Southern Co Restricted Stock Units	$0	04/01/2026		M			13(3)	(3)	(3)	Southern Company Common Stock	13	$0	305	D
Southern Co Restricted Stock Units	$0	04/01/2026		M			23(4)	(4)	(4)	Southern Company Common Stock	23	$0	539	D
Performance Restricted Stock Units	$0	04/01/2026		M			42(5)	(5)	(5)	Southern Company Common Stock	42	$0	975	D

Explanation of Responses:

1. Represents shares delivered to the Company to cover FICA withholding obligations due because Reporting Person is retirement eligible pursuant to his applicable stock grant documents. Includes 4 accrued dividend equivalent units.

2. Represents shares delivered to the Company to cover FICA withholding obligations due because Reporting Person is retirement eligible pursuant to his applicable stock grant documents.

3. Represents restricted stock units granted on January 31, 2024, payable in Southern Company common stock and will continue to vest on the third anniversary of the grant date. Additional units will be acquired with deemed dividends. Shares will be withheld upon vesting to satisfy income tax requirements.

4. Represents restricted stock units granted on February 5, 2025, payable in Southern Company common stock and will continue to vest on the remaining second and third anniversary of the grant date. Additional units will be acquired with deemed dividends. Shares will be withheld upon vesting to satisfy income tax requirements.

5. Represents restricted stock units granted on February 11, 2026, payable in Southern Company common stock and vest every year on the first, second and third anniversary of the grant date. Additional units will be acquired with deemed dividends. Shares will be withheld upon vesting to satisfy income tax requirements.

	/s/ Brittney Anderson, Attorney-in-Fact for Matthew M. Kim	04/02/2026
	** 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 4 (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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transactions did Southern Co (SO) report for Matthew M. Kim?

Southern Co reported that comptroller Matthew M. Kim exercised restricted stock unit awards into common stock and had shares withheld to cover tax obligations. These actions stem from previously granted equity compensation that vested according to their terms, rather than open-market purchases or sales.

How many Southern Co (SO) shares were used to cover taxes for Matthew M. Kim?

The filing shows that 82 shares of Southern Company common stock were delivered to the company at $96.94 per share to satisfy FICA withholding obligations. This tax-related disposition is tied to Kim’s retirement-eligible status under his stock grant documents, not a discretionary market sale.

How many Southern Co (SO) shares does Matthew M. Kim hold after these transactions?

After the reported transactions on April 1, 2026, Matthew M. Kim directly held 6,888 shares of Southern Company common stock. This figure reflects the net position following the conversion of restricted stock units and the shares delivered back to the company for tax withholding.

Were Matthew M. Kim’s Southern Co (SO) transactions open-market buys or sells?

No, the transactions were not open-market trades. They primarily involved exercises of restricted stock units into Southern Company common stock and a tax-withholding disposition, where 82 shares were delivered to the company to cover FICA obligations associated with his retirement-eligible equity awards.

What types of equity awards did Matthew M. Kim exercise at Southern Co (SO)?

Kim exercised Southern Company restricted stock units and performance restricted stock units that are payable in Southern Company common stock. These awards, granted in prior years, continue to vest on specified anniversaries of their grant dates, with additional units accruing from deemed dividends over time.

Why does the Southern Co (SO) filing mention dividend equivalent units for Matthew M. Kim?

The filing notes that certain restricted stock unit grants include accrued dividend equivalent units. These units mirror dividends paid on Southern Company common stock and increase the number of units over time, with resulting shares eventually delivered or withheld when the awards vest and taxes are settled.