[Form 4] Arqit Quantum Inc. Insider Trading Activity

Arqit Quantum Inc. Chief Executive Officer Andrew Leaver exercised restricted stock units and received additional ordinary shares.

Rhea-AI Filing Summary

Arqit Quantum Inc. Chief Executive Officer Andrew Leaver exercised restricted stock units and received additional ordinary shares. On April 1, 2026, he converted 15,625 RSUs into 15,625 ordinary shares at an exercise price of $0.00 per share.

Following the transaction, Leaver directly holds 53,346 ordinary shares and 218,750 restricted stock units. The RSUs convert into ordinary shares on a one-for-one basis and vest quarterly on April 1, July 1 and October 1 of 2026, and on January 1, April 1, July 1 and October 1 of 2027, 2028 and 2029.

Insider Trade Summary

15,625 shares exercised/converted

Exercise 2 txns

Insider Leaver Andrew

Role Chief Executive Officer

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Units	15,625	$0.00	$0.00
Exercise	Ordinary Shares	15,625	$0.00	$0.00

Holdings After Transaction: Restricted Stock Units — 218,750 contracts (Direct); Ordinary Shares — 53,346 shares (Direct)

Footnotes (2)

1. F1. Restricted Stock Units ("RSUs") convert into ARQQ ordinary shares on a one-for-one basis.
2. F2. The RSUs vest quarterly in equal installments on April 1, July 1, and 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, and January 1, April 1, July 1, and October 1, 2029.

Key Figures

RSUs exercised: 15,625 units Shares acquired: 15,625 ordinary shares Direct share holdings: 53,346 ordinary shares +1 more

4 metrics

RSUs exercised 15,625 units Converted into ordinary shares on April 1, 2026

Shares acquired 15,625 ordinary shares Received from RSU exercise at $0.00 per share

Direct share holdings 53,346 ordinary shares Directly held by CEO after the transaction

Remaining RSUs 218,750 units RSUs held by CEO after exercise, 1:1 share conversion

Key Terms

Restricted Stock Units, derivative security, Ordinary Shares, vest

4 terms

Restricted Stock Units financial

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

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.

derivative security financial

"transaction_code_description": "Exercise or conversion of derivative security""

A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.

Ordinary Shares financial

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

Ordinary shares are a type of ownership stake in a company, giving shareholders a right to participate in the company’s profits and decision-making through voting. They are similar to owning a piece of a business, and their value can rise or fall based on the company's performance. Investors buy ordinary shares to potentially earn dividends and benefit from the company's growth over time.

vest financial

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

A vest is the process by which an employee earns the right to receive certain benefits or ownership interests, such as stock or retirement funds, over time. It’s similar to earning a reward gradually, ensuring that the benefit becomes fully yours only after a set period or meeting specific conditions. This makes it important for investors because it determines when they can actually claim or use those benefits.

FAQ

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

What insider transaction did Arqit Quantum (ARQQ) CEO Andrew Leaver report?

Andrew Leaver exercised restricted stock units to acquire 15,625 Arqit Quantum ordinary shares at an exercise price of $0.00 per share. This was a derivative exercise, not an open‑market purchase or sale, and increased his directly held share position.

How many Arqit Quantum (ARQQ) shares does the CEO own after this Form 4?

After the transaction, Andrew Leaver directly holds 53,346 Arqit Quantum ordinary shares. This reflects the addition of 15,625 shares received from exercising restricted stock units, as reported in the Form 4 for the April 1, 2026 transaction date.

How many restricted stock units does the Arqit Quantum (ARQQ) CEO still hold?

Following the reported exercise, Andrew Leaver holds 218,750 restricted stock units. These RSUs convert into Arqit Quantum ordinary shares on a one‑for‑one basis, providing potential future share ownership as they vest over the disclosed multi‑year schedule.

What is the vesting schedule for the Arqit Quantum (ARQQ) CEO’s RSUs?

The RSUs vest quarterly in equal installments on April 1, July 1 and October 1, 2026, and on January 1, April 1, July 1 and October 1 of 2027, 2028 and 2029, creating a long, regular vesting pattern.

Did the Arqit Quantum (ARQQ) CEO sell any shares in this Form 4 filing?

No sale is reported in this Form 4. The filing shows an exercise or conversion of restricted stock units into 15,625 ordinary shares at $0.00 per share, increasing his direct holdings without any disclosed open‑market disposition.

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

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Accepted by SEC EDGAR 04/03/2026 - 07:22 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^*

Leaver Andrew

(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)
	Chief Executive Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/01/2026

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	04/01/2026		M		15,625	A	$0(1)	53,346	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 Stock Units	(1)	04/01/2026		M			15,625	(2)	(2)	Ordinary Shares	15,625	$0	218,750	D

Explanation of Responses:

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

2. The RSUs vest quarterly in equal installments on April 1, July 1, and 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, and January 1, April 1, July 1, and October 1, 2029.

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	04/03/2026
	** 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)