Sec Form 4 Filing - TIERNEY BRIAN X @ FIRSTENERGY CORP - 2024-03-01

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

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person TIERNEY BRIAN X 2. Issuer Name and Ticker or Trading Symbol FIRSTENERGY CORP [ FE] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) President and CEO (Last) (First) (Middle) 76 S. MAIN ST 3. Date of Earliest Transaction (MM/DD/YY) 03/01/2024 (Street) AKRON, OH44308 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 03/01/2024 A 142,698 ( 1 ) A $ 0 ( 2 ) 277,451 D Common Stock 03/01/2024 F 64,714 ( 3 ) D $ 36.305 212,737 D Common Stock 443.338 ( 4 ) I By Savings Plan

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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 RSU ( 1 ) 03/01/2024 M 142,698 ( 1 ) ( 1 ) Common Stock 142,698 $ 0 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other TIERNEY BRIAN X 76 S. MAIN ST AKRON, OH44308 X President and CEO Signatures /s/ Mary M. Swann, attorney-in-fact 03/05/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )This Form 4 is being filed to report the vesting, and automatic withholding for tax purposes, of performance-adjusted restricted stock units ("RSUs"), each of which represents a contingent right to receive an award payable in shares of common stock of FirstEnergy Corp. (the "Company") following the vesting date. The satisfaction of the performance goals for the RSUs were certified by the Company's Board of Directors on February 7, 2024, as previously reported on a Form 4 filed on February 9, 2024, and the RSUs vested on March 1, 2024. ( 2 )The RSUs were granted under the FirstEnergy Corp. 2020 Incentive Compensation Plan and, therefore, the reporting person paid no price for the RSUs. ( 3 )Represents shares of common stock of the Company automatically withheld to cover tax obligations associated with the vesting of the RSUs described in footnote 1, which transaction is exempt under Rule 16b-3. ( 4 )The Company's 401(k) Savings Plan includes a unitized fund invested in shares of common stock of the Company, in which the reporting person may invest, and includes dividend reinvestment and company match features. The number of shares reported as indirectly held in the 401(k) Savings Plan in this row is an estimate of the number of shares of the Company's common stock held in the unitized stock fund and allocated to the reporting person's account as of February 29, 2024.

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).

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