Diamondback 10% holder sells 9,079,675 shares

A ten percent owner entity associated with Lyndal Greth sold over 9 million FANG shares under Rule 144, leaving it with about 65 million shares directly held.

Rhea-AI Filing Summary

Diamondback Energy, Inc. (FANG) had a large insider sale reported by SGF FANG Holdings, LP, a ten percent owner associated with Lyndal Greth. On September 16, 2026, SGF FANG Holdings, LP sold 9,079,675 shares of common stock at $205.26 per share in a sale reported as an open-market or private transaction and disclosed as made pursuant to Rule 144 under the Securities Act of 1933. Following this transaction, the reporting entity held 64,957,047 shares of Diamondback Energy common stock directly, and no Rule 10b5-1 trading plan is reported.

Insider Trade Summary

Net Seller: 9,079,675 shares

Net Sell 1 txn

Insider SGF FANG Holdings, LP, Greth Lyndal

Role 10% Owner | 10% Owner

Sold 9,079,675 shs ($1.86B)

Type	Security	Shares	Price	Value
Sale	Common Stock F1	9,079,675	$205.26	$1.86B

Holdings After Transaction: Common Stock — 64,957,047 shares (Direct)

Footnotes (1)

1. F1. On September 16, 2026, SGF FANG Holdings, LP, a Delaware limited partnership, sold 9,079,675 shares of common stock of Diamondback Energy, Inc., par value $0.01 per share, pursuant to Rule 144 under the Securities Act of 1933, as amended.

Key Figures

Shares sold: 9,079,675 shares Sale price per share: $205.26 per share Shares held after transaction: 64,957,047 shares +1 more

4 metrics

Shares sold 9,079,675 shares Common stock sold by SGF FANG Holdings, LP on September 16, 2026

Sale price per share $205.26 per share Reported price for the September 16, 2026 common stock sale

Shares held after transaction 64,957,047 shares Directly held by SGF FANG Holdings, LP after the reported sale

Net shares sold in filing 9,079,675 shares Net sell volume across all reported transactions in this Form 4

Key Terms

Rule 144, ten percent owner, Securities Act of 1933, par value

4 terms

Rule 144 regulatory

"sold 9,079,675 shares of common stock ... pursuant to Rule 144 under the Securities Act"

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

ten percent owner regulatory

"SGF FANG Holdings, LP is identified as a ten percent owner"

Securities Act of 1933 regulatory

"pursuant to Rule 144 under the Securities Act of 1933, as amended"

par value financial

"common stock of Diamondback Energy, Inc., par value $0.01 per share"

Par value is the fixed amount printed on a bond or stock that represents its original value when issued. It’s like the face value of a coin or bill—what the issuer promises to pay back or the starting price of a stock—though it often doesn’t change with market prices. It matters because it helps determine certain financial details, like how much the company will pay back at maturity.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction in FANG stock did SGF FANG Holdings, LP report?

SGF FANG Holdings, LP reported a sale of 9,079,675 shares of Diamondback Energy, Inc. common stock on September 16, 2026, in a transaction described as a sale in the open market or a private transaction at a reported price of $205.26 per share.

How many FANG shares does the reporting entity hold after this Form 4 transaction?

After the reported sale, SGF FANG Holdings, LP directly holds 64,957,047 shares of Diamondback Energy, Inc. common stock, as stated in the filing’s post-transaction ownership figure.

Was the SGF FANG Holdings, LP sale of FANG shares made under Rule 144?

Yes. A footnote states that on September 16, 2026, SGF FANG Holdings, LP sold 9,079,675 shares of Diamondback Energy common stock pursuant to Rule 144 under the Securities Act of 1933.

Is the SGF FANG Holdings, LP transaction in FANG tied to a Rule 10b5-1 trading plan?

The filing’s Rule 10b5-1 checkbox is not checked, and no footnote describes a trading plan, so no Rule 10b5-1 plan is reported for this transaction.

Who are the reporting persons on this FANG Form 4 filing?

The reporting persons are SGF FANG Holdings, LP, a ten percent owner, and Lyndal Greth, also identified as a ten percent owner. The sale itself is attributed to SGF FANG Holdings, LP under the footnote description.

What type of security was sold in the FANG insider transaction?

The transaction involved Common Stock of Diamondback Energy, Inc., with a par value of $0.01 per share, as specified in the footnote describing the Rule 144 sale.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/17/2026 - 05:09 PM Accepted by SEC EDGAR 09/17/2026 - 05:08 PM Learn about SEC filing dates

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^*

SGF FANG Holdings, LP

(Last) (First) (Middle)

C/O SGF CAPITAL LLC, KEVIN T. KEEN

8111 DOUGLAS AVE., SUITE 1200

(Street)

DALLAS TEXAS 75225

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Diamondback Energy, Inc. [ FANG ]

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/16/2026

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

	Form filed by One Reporting Person
X	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
Common Stock	09/16/2026		S(1)		9,079,675	D	$205.26	64,957,047	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

1. Name and Address of Reporting Person^*

SGF FANG Holdings, LP

(Last) (First) (Middle)

C/O SGF CAPITAL LLC, KEVIN T. KEEN

8111 DOUGLAS AVE., SUITE 1200

(Street)

DALLAS TEXAS 75225

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

Greth Lyndal

(Last) (First) (Middle)

C/O SGF CAPITAL LLC, KEVIN T. KEEN

8111 DOUGLAS AVENUE, SUITE 1200

(Street)

DALLAS TEXAS 75225

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

Explanation of Responses:

1. On September 16, 2026, SGF FANG Holdings, LP, a Delaware limited partnership, sold 9,079,675 shares of common stock of Diamondback Energy, Inc., par value $0.01 per share, pursuant to Rule 144 under the Securities Act of 1933, as amended.

	/s/ Kevin T. Keen, Attorney in fact	09/17/2026
	** 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)