Form: 4

Statement of changes in beneficial ownership of securities

April 17, 2026

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
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 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*
Lefebvre d'Ovidio Manfredi
(Last) (First) (Middle)
3 ORCHARD PLACE
(Street)
LONDON X0 SW1H 0BF
(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
Arqit Quantum Inc. [ ARQQ ] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
X Director 10% Owner
Officer (give title below) Other (specify below)
3. Date of Earliest Transaction (Month/Day/Year)
04/15/2026
4. 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 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
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
Business Combination Warrants (right to buy) (1) 04/15/2026 S 713 (1) 09/03/2026 Ordinary Shares 713 $3 29,151.84 I Beneficially owned through Heritage Assets SCSp
Business Combination Warrants (right to buy) (1) 04/16/2026 S 159 (1) 09/03/2026 Ordinary Shares 159 $3.1 28,992.8 I Beneficially owned through Heritage Assets SCSp
Explanation of Responses:
1. On September 19, 2024, Arqit Quantum Inc. (ARQQ) announced the implementation of a reverse stock split whereby every 25 outstanding ARQQ ordinary shares were consolidated into one ordinary share, par value $0.0025 per share. Each Business Combination Warrant has an exercise price of $11.50 and can be exercised at any time, at the holder's election, to purchase 0.04 of an ARQQ ordinary share on a post-reverse stock split basis, and cannot be exercised for fractional shares. Accordingly, on a post-reverse stock split basis holders of Business Combination Warrants are required to exercise at least 25 Business Combination Warrants in order to receive one whole ARQQ ordinary share at an aggregate exercise price of $287.50 per whole ARQQ ordinary share. The reporting person beneficially owns 724,820 Business Combination Warrants, which, if exercised in full, would be equivalent to 28,992.8 ARQQ ordinary shares on a post-reverse stock split basis.
Remarks:
Due to the issuer's status as a foreign private issuer pursuant to Rule 3a12-3(b) under the Securities Exchange Act of 1934 (the "Act"), the reporting person's transactions in the issuer's securities are exempt from Sections 16(b) and 16(c) of the Act.
/s/ Manfredi Lefebvre d'Ovidio 04/17/2026
** 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.