Arqit Quantum director converts grant into 1,021 shares

The units vested within the week of the grant and converted into ordinary shares on a one-for-one basis.

Rhea-AI Filing Summary

Arqit Quantum Inc. director Garth Ritchie received 1,021 restricted share units on October 15, 2026. On October 16, he converted 1,021 RSUs into 1,021 ordinary shares; the units vested within the week of the grant date and convert into ordinary shares on a one-for-one basis. His reported direct holdings after the conversion were 106,855 ordinary shares.

Insider Trade Summary

1,021 shares exercised/converted

Exercise 3 txns

Insider Ritchie Garth

Role Director

Type	Security	Shares	Price	Value
Exercise	Restricted Share Units F1	1,021	$0.00	$0.00
Exercise	Ordinary Shares F1	1,021	$0.00	$0.00
Grant/Award	Restricted Share Units F1	1,021	$0.00	$0.00

Holdings After Transaction: Restricted Share Units — 0 contracts (Direct); Ordinary Shares — 106,855 shares (Direct)

Footnotes (1)

1. F1. Restricted Stock Units ("RSUs") convert into ARQQ ordinary shares on a one-for-one basis. The RSUs vested within the week of the grant date.

Key Figures

RSUs granted: 1,021 RSUs RSUs converted: 1,021 RSUs Ordinary shares acquired on conversion: 1,021 ordinary shares +1 more

4 metrics

RSUs granted 1,021 RSUs October 15, 2026

RSUs converted 1,021 RSUs October 16, 2026

Ordinary shares acquired on conversion 1,021 ordinary shares October 16, 2026

Direct ordinary-share holdings after conversion 106,855 ordinary shares October 16, 2026

Key Terms

Restricted Stock Units, one-for-one basis, foreign private issuer

3 terms

Restricted Stock Units financial

"Restricted Stock Units ("RSUs") convert into ARQQ ordinary shares"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

one-for-one basis financial

"convert into ARQQ ordinary shares on a one-for-one basis"

foreign private issuer regulatory

"issuer's status as a foreign private issuer"

A foreign private issuer is a company organized outside the United States that meets tests showing it is primarily foreign-controlled and therefore qualifies for a different set of U.S. reporting rules. For investors, that means the company files less frequent or differently formatted disclosures with U.S. regulators and may follow home-country accounting and governance practices, so buying its stock is like dining at a well-reviewed restaurant that follows its home kitchen’s rules instead of the local menu — you get access but should check what standards apply.

FAQ

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

How many ARQQ shares did director Garth Ritchie receive?

Garth Ritchie, a director of Arqit Quantum Inc. (ARQQ), converted 1,021 RSUs into 1,021 ordinary shares on October 16, 2026. He received the 1,021-RSU grant on October 15, 2026, and his reported direct ordinary-share holdings after the conversion were 106,855.

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

Form 4 Insider Transactions: What Each Field Means →

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Available on EDGAR 10/20/2026 - 05:35 PM EDT Accepted by SEC EDGAR 10/20/2026 - 05:34 PM EDT 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^*

Ritchie Garth

(Last) (First) (Middle)

3 ORCHARD PLACE

(Street)

LONDON SW1H 0BF

(City) (State) (Zip)

UNITED KINGDOM

(Country)

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)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
10/15/2026

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

X	Form filed by One Reporting Person
	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
Ordinary Shares	10/16/2026		M		1,021	A	$0(1)	106,855	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
Restricted Share Units	(1)	10/15/2026		A		1,021		(1)	(1)	Ordinary Shares	1,021	$0	1,021	D
Restricted Share Units	(1)	10/16/2026		M			1,021	(1)	(1)	Ordinary Shares	1,021	$0	0	D

Explanation of Responses:

1. Restricted Stock Units ("RSUs") convert into ARQQ ordinary shares on a one-for-one basis. The RSUs vested within the week of the grant date.

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. Ex.24 - Power of Attorney

	/s/ Noleen McDonnell, as Attorney-in-Fact	10/20/2026
	** 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)