Sec Form 3 Filing - Protiva Brian @ ADTRAN Holdings, Inc. - 2022-07-15

FORM 3 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 Protiva Brian 2. Issuer Name and Ticker or Trading Symbol ADTRAN Holdings, Inc. [ ADTN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) CEO of ADVA (Last) (First) (Middle) C/O ADTRAN HOLDINGS, INC., 901 EXPLORER BLVD. 3. Date of Earliest Transaction (MM/DD/YY) 07/15/2022 (Street) HUNTSVILLE, AL35806 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 No securities are beneficially owned 0 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 (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

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Protiva Brian C/O ADTRAN HOLDINGS, INC. 901 EXPLORER BLVD. HUNTSVILLE, AL35806 X CEO of ADVA Signatures /s/ Michael Foliano, by power of attorney 07/18/2022 Signature of Reporting Person Date

Explanation of Responses:

Remarks: Immediately following the Closing of the Exchange Offer (as defined in that certain Business Combination Agreement dated as of August 30, 2021, by and among ADTRAN, Inc., ADVA Optical Networking SE ("ADVA"), the Issuer (f/k/a Acorn HoldCo, Inc.), and Acorn MergeCo, Inc.), the reporting person became a member of the Issuer's Board of Directors (the "Board"). In addition, though the reporting person is not a corporate officer of the Issuer, he has been designated as an officer as defined in Rule 16a-1(f) of the Securities Exchange Act of 1934, as amended, by the Board as of the date hereof by virtue of his position as Chief Executive Officer of ADVA, a subsidiary of the Issuer.

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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