SEC Form 4 · accession 0001104659-26-076365

Arqit Quantum Inc. · ARQQ

Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗

Reporting owner

d'Ovidio Manfredi Lefebvre

Director

Period of report

Jun 17, 2026

Accepted (ET)

Jun 22, 2026 · 4:05 pm EDT

Rule 10b5-1 plan

box not checked

Issuer CIK

0001859690

Table I — non-derivative securities

No Table I lines on this filing.

Table II — derivative securities

Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	Owned after	D/I
Business Combination Warrants (right to buy)^F1	—	Jun 17, 2026	S	880	D	—	Sep 3, 2026	Ordinary Shares	880	17,666	I
Business Combination Warrants (right to buy)^F1	—	Jun 18, 2026	S	524	D	—	Sep 3, 2026	Ordinary Shares	524	17,142	I

Explanation of responses

F1On 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 428,544 Business Combination Warrants, which, if exercised in full, would be equivalent to 17,141.76 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.