Arqit Quantum director Garth Ritchie sells 127 shares

The reported RSUs carry quarterly vesting schedules, with one award schedule extending through October 1, 2028.

Rhea-AI Filing Summary

Arqit Quantum Inc. (ARQQ) director Garth Ritchie converted 248 restricted share units into ordinary shares on October 5, 2026; the RSUs convert one-for-one. The corresponding ordinary-share records report 248 shares acquired. Ritchie also sold 127 ordinary shares at $23.7847 per share that day. No Rule 10b5-1 plan is reported.

Insider Trade Summary

Exercise and sale activity reported; no spread calculated

Exercise and Sale 9 txns

Insider Ritchie Garth

Role Director

Sold 127 shs ($3K)

Approx. gross sale proceeds $3K

Type	Security	Shares	Price	Value
Exercise	Restricted Share Units F2	16	$0.00	$0.00
Exercise	Restricted Share Units F2	66	$0.00	$0.00
Exercise	Restricted Share Units F3	83	$0.00	$0.00
Exercise	Restricted Share Units F4	83	$0.00	$0.00
Exercise	Ordinary Shares F1	16	$0.00	$0.00
Exercise	Ordinary Shares F1	66	$0.00	$0.00
Exercise	Ordinary Shares F1	83	$0.00	$0.00
Exercise	Ordinary Shares F1	83	$0.00	$0.00
Sale	Ordinary Shares	127	$23.7847	$3K

Holdings After Transaction: Restricted Share Units — 3,751 contracts (Direct); Ordinary Shares — 105,952 shares (Direct)

Footnotes (4)

1. F1. The Restricted Share Units ("RSUs") convert into ARQQ ordinary shares on a one-for-one basis.
2. F2. The RSUs vest quarterly in equal installments on October 1, 2026, and January 1, April 1, and July 1, 2027.
3. F3. The RSUs vest quarterly in equal installments on October 1, 2026, and January 1, April 1, July 1, and October 1, 2027.
4. F4. The RSUs vest quarterly in equal installments on October 1, 2026, and January 1, April 1, July 1, and October 1, 2027, and January 1, April 1, July 1, and October 1, 2028.

Key Figures

RSUs converted: 248 RSUs Ordinary shares acquired: 248 shares Ordinary shares sold: 127 shares +2 more

5 metrics

RSUs converted 248 RSUs Converted into ordinary shares on October 5, 2026

Ordinary shares acquired 248 shares Corresponding ordinary-share entries on October 5, 2026

Ordinary shares sold 127 shares October 5, 2026

Sale price $23.7847 per share Sale on October 5, 2026

RSU conversion ratio one-for-one RSUs convert into ordinary shares

Key Terms

Restricted Share Units, one-for-one basis, vest quarterly in equal installments, foreign private issuer

4 terms

Restricted Share Units financial

"The Restricted Share Units ("RSUs") convert into ARQQ ordinary shares"

Restricted share units (RSUs) are a promise from a company to give an employee or service provider actual shares or cash equal to the shares after certain conditions are met, typically staying with the company for a set time or hitting performance targets. Think of them like a time-locked gift card that becomes usable only after you’ve earned it. For investors, RSUs matter because they align employee incentives with company performance and can increase the number of shares outstanding over time, diluting existing ownership and affecting earnings per share.

one-for-one basis financial

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

vest quarterly in equal installments financial

"The RSUs vest quarterly in equal installments"

foreign private issuer regulatory

"Due to the 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 Garth Ritchie sell, and at what price?

Garth Ritchie, a director of Arqit Quantum Inc., sold 127 ordinary shares at $23.7847 per share on October 5, 2026. No Rule 10b5-1 plan is reported.

How many ARQQ RSUs did Garth Ritchie convert?

Ritchie converted 248 restricted share units into ordinary shares on October 5, 2026. The RSUs convert into ordinary shares on a one-for-one basis.

When do Garth Ritchie's ARQQ restricted share units vest?

The 16- and 66-unit RSU entries vest quarterly in equal installments on October 1, 2026, and January 1, April 1, and July 1, 2027. One 83-unit entry has installments through October 1, 2027; the other has installments through October 1, 2028.

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

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Available on EDGAR 10/07/2026 - 07:44 PM Accepted by SEC EDGAR 10/07/2026 - 07:44 PM 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)
10/05/2026

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	10/05/2026		M		16	A	$0(1)	105,847	D
Ordinary Shares	10/05/2026		M		66	A	$0(1)	105,913	D
Ordinary Shares	10/05/2026		M		83	A	$0(1)	105,996	D
Ordinary Shares	10/05/2026		M		83	A	$0(1)	106,079	D
Ordinary Shares	10/05/2026		S		127	D	$23.7847	105,952	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	(2)	10/05/2026		M			16	(2)	(2)	Ordinary Shares	16	$0	816	D
Restricted Share Units	(2)	10/05/2026		M			66	(2)	(2)	Ordinary Shares	66	$0	750	D
Restricted Share Units	(3)	10/05/2026		M			83	(3)	(3)	Ordinary Shares	83	$0	1,001	D
Restricted Share Units	(4)	10/05/2026		M			83	(4)	(4)	Ordinary Shares	83	$0	2,000	D

Explanation of Responses:

1. The Restricted Share Units ("RSUs") convert into ARQQ ordinary shares on a one-for-one basis.

2. The RSUs vest quarterly in equal installments on October 1, 2026, and January 1, April 1, and July 1, 2027.

3. The RSUs vest quarterly in equal installments on October 1, 2026, and January 1, April 1, July 1, and October 1, 2027.

4. The RSUs vest quarterly in equal installments on October 1, 2026, and January 1, April 1, July 1, and October 1, 2027, and January 1, April 1, July 1, and October 1, 2028.

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/ Noleen McDonnell, as Attorney-in-Fact	10/07/2026
	** 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)