Arqit Quantum manager Nilan sells 522 shares

A total of 2,879 RSUs vested October 1, 2026; remaining RSUs vest quarterly through October 1, 2028.

Rhea-AI Filing Summary

Arqit Quantum Inc. General Manager-US Nicholas William Nilan reported converting 959 restricted share units into 959 ordinary shares on October 5, 2026, and selling 522 ordinary shares at 23.7847 per share that day. No Rule 10b5-1 plan is reported for the sale.

Nilan reported 5,752 RSUs following the conversion. Each RSU represents a contingent right to receive one ordinary share.

Insider Trade Summary

Exercise and sale activity reported; no spread calculated

Exercise and Sale 3 txns

Insider Nilan Nicholas William

Role General Manager-US

Sold 522 shs ($12K)

Approx. gross sale proceeds $12K

Type	Security	Shares	Price	Value
Exercise	Restricted Share Units F2	959	$0.00	$0.00
Exercise	Ordinary Shares F1	959	$0.00	$0.00
Sale	Ordinary Shares	522	$23.7847	$12K

Holdings After Transaction: Restricted Share Units — 5,752 contracts (Direct); Ordinary Shares — 904 shares (Direct)

Footnotes (2)

1. F1. The Restricted Share Units ("RSUs") convert into ARQQ ordinary shares on a one-for-one basis.
2. F2. Each restricted stock unit ("RSU") represents a contingent right to receive one ARQQ ordinary share. 2,879 RSUs vested on October 1, 2026 and the remaining RSUs vest quarterly in equal installments on January 1, April 1, July 1, and October 1, 2027, and January 1, April 1, July 1, and October 1, 2028.

Key Figures

Restricted share units converted: 959 restricted share units Ordinary shares acquired: 959 ordinary shares Ordinary shares sold: 522 ordinary shares +3 more

6 metrics

Restricted share units converted 959 restricted share units October 5, 2026

Ordinary shares acquired 959 ordinary shares Conversion on October 5, 2026

Ordinary shares sold 522 ordinary shares October 5, 2026

Sale price 23.7847 per share Sale on October 5, 2026

RSUs following conversion 5,752 RSUs Reported following the October 5, 2026 transaction

RSUs vested 2,879 RSUs Vested October 1, 2026

Key Terms

Restricted Share Units, one-for-one basis, contingent right

3 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"

contingent right financial

"represents a contingent right to receive one ARQQ ordinary share"

FAQ

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

How many ARQQ shares did Nicholas William Nilan sell, and at what price?

Nicholas William Nilan, General Manager-US, reported selling 522 Arqit Quantum ordinary shares at 23.7847 per share on October 5, 2026. No Rule 10b5-1 plan is reported for the sale.

When do Nicholas William Nilan’s ARQQ RSUs vest?

The RSU terms state that 2,879 RSUs vested on October 1, 2026, and remaining RSUs vest in equal quarterly installments on January 1, April 1, July 1 and October 1, 2027, and January 1, April 1, July 1 and October 1, 2028.

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

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Available on EDGAR 10/07/2026 - 07:46 PM Accepted by SEC EDGAR 10/07/2026 - 07:45 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^*

Nilan Nicholas William

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	General Manager-US

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		959	A	$0(1)	1,863	D
Ordinary Shares	10/05/2026		S		522	D	$23.7847	904	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			959	(2)	(2)	Ordinary Shares	959	$0	5,752	D

Explanation of Responses:

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

2. Each restricted stock unit ("RSU") represents a contingent right to receive one ARQQ ordinary share. 2,879 RSUs vested on October 1, 2026 and the remaining RSUs vest quarterly in equal installments on 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)