# EDGAR Filing Document

**Accession Number:** 0001859690
**File Stem:** 0001104659-25-091701
**Filing Date:** 2025-9
**Character Count:** 133650
**Document Hash:** 302fadd19aa3f33dd767626e12c3d9f9
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-25-091701.hdr.sgml**: 20250919

**ACCESSION NUMBER**: 0001104659-25-091701

**CONFORMED SUBMISSION TYPE**: 424B3

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20250919

**DATE AS OF CHANGE**: 20250919

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Arqit Quantum Inc.
- **CENTRAL INDEX KEY:** 0001859690
- **STANDARD INDUSTRIAL CLASSIFICATION:** SERVICES-PREPACKAGED SOFTWARE [7372]
- **ORGANIZATION NAME:** 06 Technology
- **EIN:** 000000000
- **STATE OF INCORPORATION:** E9
- **FISCAL YEAR END:** 0930

**FILING VALUES:**
- **FORM TYPE:** 424B3
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-289939
- **FILM NUMBER:** 251327359

**BUSINESS ADDRESS:**
- **STREET 1:** 3 ORCHARD PLACE
- **CITY:** LONDON
- **STATE:** X0
- **ZIP:** SW1H 0BF
- **BUSINESS PHONE:** 44 203 91 70155

**MAIL ADDRESS:**
- **STREET 1:** 3 ORCHARD PLACE
- **CITY:** LONDON
- **STATE:** X0
- **ZIP:** SW1H 0BF

[**TABLE OF CONTENTS**](#TOC)

#### Filed Pursuant to Rule 424(b)(3) Registration No. 333-289939

#### PROSPECTUS

### ARQIT QUANTUM INC.

### 11,514,816 Ordinary Shares Offered by Selling Securityholders 5,440,000 Ordinary Shares Underlying Warrants
This prospectus relates to the offer and sale from time to time by the selling securityholders named in this prospectus (the "**Selling Securityholders**") of up to 11,514,816 of our ordinary shares, par value $0.0025 per share ("**Ordinary Shares**"). In addition, this prospectus relates to the issuance by us of up to 5,440,000 Ordinary Shares, that are issuable by us upon the exercise of the September 2024 Warrants (as defined below).

The Selling Securityholders may offer, sell or distribute all or a portion of the Ordinary Shares registered hereby publicly or through private transactions at prevailing market prices or at negotiated prices. We will not receive any of the proceeds from such sales of the Ordinary Shares, except with respect to amounts received by us upon the exercise of the September 2023 Investor Warrants and September 2024 Warrants (each as defined below). We will bear all costs, expenses and fees in connection with the registration of these Ordinary Shares, including with regard to compliance with state securities or "blue sky" laws. The Selling Securityholders will bear all commissions and discounts, if any, attributable to their sale of Ordinary Shares. See "Plan of Distribution."

Our Ordinary Shares are listed on The Nasdaq Capital Market under the symbol "ARQQ". On September 18, 2025, the last reported sales price of our Ordinary Shares was $37.40 per share.

We are a "foreign private issuer," and an "emerging growth company" each as defined under the federal securities laws, and, as such, we are subject to reduced public company reporting requirements. See the section entitled "*Prospectus Summary — Implications of Being an Emerging Growth Company and a Foreign Private Issuer*" for additional information.

 **Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described under the heading "Risk Factors" beginning on page [9](#tRIFA) of this prospectus, and under similar headings in any amendment or supplements to this prospectus.** 

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

#### The date of this prospectus is September 19, 2025.

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#### **TABLE OF CONTENTS**

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| | |
|:---|:---|
| | **Page**  |
| [ABOUT THIS PROSPECTUS](#tATP)  | [1](#tATP) |
| [INDUSTRY AND MARKET DATA](#tIAMD)  | [2](#tIAMD) |
| [FREQUENTLY USED TERMS](#tFUT)  | [3](#tFUT) |
| [CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS](#tCNRF)  | [5](#tCNRF) |
| [PROSPECTUS SUMMARY](#tPRSU)  | [6](#tPRSU) |
| [THE OFFERING](#tTHOF)  | [8](#tTHOF) |
| [RISK FACTORS](#tRIFA)  | [9](#tRIFA) |
| [CAPITALIZATION](#tCAP)  | [11](#tCAP) |
| [USE OF PROCEEDS](#tUOP)  | [12](#tUOP) |
| [DIVIDEND POLICY](#tDIPO)  | [13](#tDIPO) |
| [DESCRIPTION OF SECURITIES](#tDOS)  | [14](#tDOS) |
| [SELLING SECURITYHOLDERS](#tSESE)  | [25](#tSESE) |
| [TAX CONSIDERATIONS](#tTACO)  | [26](#tTACO) |
| [PLAN OF DISTRIBUTION](#tPOD)  | [33](#tPOD) |
| [EXPENSES RELATED TO THE OFFERING](#tERTT)  | [35](#tERTT) |
| [LEGAL MATTERS](#tLEMA)  | [36](#tLEMA) |
| [EXPERTS](#tEXP)  | [37](#tEXP) |
| [WHERE YOU CAN FIND MORE INFORMATION](#tWYCF)  | [38](#tWYCF) |
| [INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE](#tIOCD)  | [39](#tIOCD) |

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#### ABOUT THIS PROSPECTUS
This prospectus is part of a registration statement that we filed with the SEC, utilizing a "shelf" registration process. By using a shelf registration statement, the Selling Securityholders may sell securities from time to time and in one or more offerings. Any prospectus supplement or free writing prospectus that we file in connection with any specific offering by the Selling Securityholders may add, update or change information contained in this prospectus. If there is any inconsistency between the information in this prospectus and any applicable prospectus supplement or free writing prospectus, you should rely on the prospectus supplement or free writing prospectus, as applicable. Before purchasing any securities, you should read this prospectus, any applicable prospectus supplement and any applicable free writing prospectus, together with the additional information described under the heading "*Where You Can Find More Information*" and "*Incorporation of Certain Documents by Reference*."

 **You should rely only on the information contained in or incorporated by reference into this prospectus and any applicable prospectus supplement. We have not authorized anyone to provide you with any information or to make any representations other than those contained in this prospectus, or in any applicable prospectus supplement prepared by or on behalf of us or to which we have referred you. You should assume that the information appearing in this prospectus or any prospectus supplement is accurate only as of the date on its respective cover page and that any information incorporated by reference into any of the foregoing is accurate only as of the date of such document incorporated by reference. Our business, financial condition, results of operations and prospects may have changed since those dates.** 

For investors outside the United States: we have not done anything that would permit offerings under this prospectus, or possession or distribution of this prospectus, in any jurisdiction where action for that purpose is required, other than in the United States. Persons outside the United States who come into possession of this prospectus must inform themselves about, and observe any restrictions relating to, the offering of the Ordinary Shares and the distribution of this prospectus outside of the United States.

#### September 2023 Registered Direct Offering
On September 8, 2023, the Company entered into a securities purchase agreement pursuant to which existing shareholders Heritage Assets SCSP, Ropemaker Nominees Limited and Carlo Calabria purchased a total of 317,408 Ordinary Shares (the "**September 2023 Ordinary Shares**"), together with warrants to purchase up to 317,408 Ordinary Shares (the "**September 2023 Investor Warrants**") in a registered direct offering. The September 2023 Ordinary Shares and Ordinary Shares issuable upon exercise of the September 2023 Investor Warrants are being registered for resale hereunder.

#### September 2024 Registered Direct Offering and Private Placement
On September 30, 2024, the Company entered into a securities purchase agreement pursuant to which existing shareholders Heritage Assets SCSP, Ropemaker Nominees Limited, Carlo Calabria and Garth Ritchie purchased a total of 5,440,000 Ordinary Shares (the "**September 2024 Ordinary Shares**") in a registered direct offering and, in a concurrent private placement, warrants to purchase up to 5,440,000 Ordinary Shares (the "**September 2024 Warrants**"). The September 2024 Ordinary Shares and Ordinary Shares issuable upon exercise of the September 2024 Warrants are being registered for resale hereunder. In addition, we are registering hereunder the issuance of up to 5,440,000 Ordinary Shares upon exercise of the September 2024 Warrants.

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#### INDUSTRY AND MARKET DATA
In this prospectus and the documents incorporated by reference in this prospectus, we present industry data, information and statistics regarding the markets in which the Company competes as well as publicly available information, industry and general publications and research and studies conducted by third parties. This information is supplemented where necessary with the Company's own internal estimates and information obtained from discussions with its customers, taking into account publicly available information about other industry participants and the Company's management's judgment where information is not publicly available.

Industry publications, research, studies and forecasts generally state that the information they contain has been obtained from sources believed to be reliable, but that the accuracy and completeness of such information is not guaranteed. Forecasts and other forward-looking information obtained from these sources are subject to the same qualifications and uncertainties as the other forward-looking statements in this prospectus or any document incorporated by reference into this prospectus. These forecasts and forward- looking information are subject to uncertainty and risk due to a variety of factors, including those described under the section entitled "*Risk Factors*." These and other factors could cause results to differ materially from those expressed in any forecasts or estimates.

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#### FREQUENTLY USED TERMS
Unless otherwise stated or unless the context otherwise requires, the terms "the Company," "the registrant," "our company," "the company," "we," "us," "our," "ours," and "Arqit" refer to Arqit Quantum Inc.

In this prospectus, unless the context otherwise requires:

"*Arqit*" or "*Company*" means Arqit Quantum Inc., a Cayman Islands exempted limited liability company with registered number 374857 and whose registered office is at Maples Corporate Services Limited, PO Box 309, Ugland House, Grand Cayman, KY1-1104, Cayman Islands.

"*Articles*" means the memorandum and articles of association of Arqit.

"*Business Combination*" means the transaction completed on September 3, 2021 in connection with which Centricus Acquisition Corp. merged with and into Arqit Quantum Inc., with Arqit Quantum Inc. as the surviving entity, following which Arqit Quantum Inc. acquired all of the outstanding share capital of Arqit Limited, with Arqit Limited becoming a wholly- owned subsidiary of Arqit Quantum Inc.

"*Cayman Companies Act*" means the Companies Act (As Revised) of the Cayman Islands, as may be amended from time to time.

"*Code*" means the U.S. Internal Revenue Code of 1986, as amended.

"*Exchange Act*" means the U.S. Securities Exchange Act of 1934, as amended.

"*February 2023 Investor Warrants*" means Arqit's 300,002 outstanding warrants to purchase its Ordinary Shares at an exercise price of $50.00 per share, which became exercisable on February 22, 2023.

"*February 2023 Placement Agent Warrants*" means Arqit's 22,001 outstanding warrants to purchase its Ordinary Shares at an exercise price of $62.50 per share, which became exercisable on February 22, 2023.

"*IRS*" means the U.S. Internal Revenue Service.

"*JOBS Act*" means the Jumpstart Our Business Startups Act of 2012, as amended.

"*Nasdaq*" means the Nasdaq Capital Market.

"*Ordinary Shares*" means the ordinary shares, with $0.0025 par value per share, of the Company.

"*PFIC*" means passive foreign investment company within the meaning of Section 1297 of the Code.

"*prospectus*" means the prospectus included in this registration statement on Form F-3 (Registration No. 333-289939) filed with the SEC.

"*Public Warrants*" means the 13,038,904 outstanding warrants that were assumed by Arqit in connection with the closing of the Business Combination and that are listed on Nasdaq under the symbol "ARQQW". Each Public Warrant can be exercised to purchase 0.04 of an Ordinary Share, and cannot be exercised for fractional shares, meaning that holders of Public Warrants are required to exercise at least 25 Public Warrants in order to receive one whole Ordinary Share at an aggregate exercise price of $287.50 per whole Ordinary Share.

"*QEF election*" means a "qualified electing fund" election under Section 1295 of the Code.

"*Sarbanes-Oxley Act*" means the Sarbanes-Oxley Act of 2002.

"*SEC*" means the U.S. Securities Exchange Commission.

"*Securities Act*" means the U.S. Securities Act of 1933, as amended.

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"*September 2023 Investor Warrants*" means Arqit's 317,408 outstanding warrants to purchase its Ordinary Shares at an exercise price of $19.50 per share, which became exercisable on September 12, 2023.

"*September 2023 Placement Agent Warrants*" means Arqit's 28,207 outstanding warrants to purchase its Ordinary Shares at an exercise price of $24.37 per share, which became exercisable on September 12, 2023.

"*September 2024 Warrants*" means Arqit's 5,440,000 outstanding warrants to purchase its Ordinary Shares at an exercise price of $2.50 per share, 4,720,000 of which will become exercisable on September 30, 2025, and 720,000 of which will become exercisable on October 9, 2025 (in each case, the date that is one year from the issuance date).

"*U.S. dollar*" or "$" means the legal currency of the United States.

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#### CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS
This prospectus and the documents incorporated in it by reference contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, or the Securities Act, Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act, and the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995, which are based on our management's beliefs and assumptions and on information currently available to our management. Forward- looking statements include information concerning our possible or assumed future results of our business, financial condition, results of operations, liquidity, plans and objectives. Forward-looking statements include all statements that are not historical facts and in some cases can be identified by terminology such as "believe," "may," "estimate," "continue," "anticipate," "intend," "should," "plan," "expect," "predict," "potential," or the negative of these terms or other similar expressions that convey uncertainty of future events or outcomes.

Our ability to predict the results of our operations or the effects of various events on our operating results is inherently uncertain. Therefore, we caution you to consider carefully the matters described under the caption "Risk Factors" and certain other matters discussed in this prospectus, the documents incorporated by reference in this prospectus, and other publicly available sources. Such factors and many other factors beyond the control of our management could cause our actual results, level of activity, performance or achievements to differ materially from any future results, level of activity, performance or achievements that may be expressed or implied by the forward-looking statements. Unless we are required to do so under U.S. federal securities laws or other applicable laws, we do not intend to update or revise any forward- looking statements.

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#### PROSPECTUS SUMMARY
This summary highlights selected information from this prospectus and does not contain all of the information that is important to you in making an investment decision. This summary is qualified in its entirety by the more detailed information included in this prospectus. Before making your investment decision with respect to our securities, you should carefully read this entire prospectus, including the section entitled "Risk Factors," the financial statements and related notes thereto, the documents incorporated by reference in this prospectus and the other documents to which this prospectus refers.

Unless otherwise indicated or the context otherwise requires, references in this prospectus to "Company," "we," "our," "us" and other similar terms refer to Arqit Quantum Inc. and our consolidated subsidiaries.

#### Overview
Arqit is a cybersecurity company that supplies a unique symmetric key agreement encryption software service which makes the communications links of any networked device, cloud machine or data at rest secure against both current and future forms of attack on encryption — even from a quantum computer. The Arqit SKA-Platform<sup>TM</sup>, uses a lightweight software agent that allows end point devices to create encryption keys locally in partnership with any number of other devices. The keys are computationally secure and facilitate "Zero Trust Network Access". It can create limitless volumes of keys with any group size and refresh rate and can regulate the secure entrance and exit of a device in a group. The agent is lightweight and will thus run on the smallest of end point devices. The product sits within a growing portfolio of granted patents. It also works in a standards compliant manner which does not oblige customers to make a disruptive rip and replace of their technology.

The mailing address for Arqit's principal executive offices is 1st Floor, 3 Orchard Place, London, SW1H 0BF, United Kingdom and our telephone number is +44 203 91 70155.

#### Implications of Being an Emerging Growth Company and a Foreign Private Issuer

#### Emerging Growth Company
Arqit is an "emerging growth company," as defined in Section 2(a) of the Securities Act, as modified by the Jumpstart Our Business Startups Act of 2012 (the "JOBS Act"). As such, it is eligible to take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not "emerging growth companies" including, but not limited to, not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act of 2002 (the "Sarbanes- Oxley Act"). Additionally, to the extent that Arqit ceases to become a foreign private issuer, emerging growth company status would allow it to include reduced disclosure obligations regarding executive compensation in its periodic reports and to be exempt from the requirements of holding a nonbinding advisory vote on executive compensation and shareholder approval of any golden parachute payments not previously approved. If some investors find Arqit's securities less attractive as a result, there may be a less active trading market for Arqit's securities and the prices of Arqit's securities may be more volatile.

Arqit will remain an emerging growth company until the earlier of: (1) the last day of the fiscal year (a) following the fifth anniversary of the closing of the Business Combination, (b) in which it has total annual gross revenues of at least $1.235 billion, or (c) in which it is deemed to be a large accelerated filer, which means the market value of its Ordinary Shares that are held by non-affiliates exceeds $700 million as of the end of the prior fiscal year's second fiscal quarter; and (2) the date on which it has issued more than $1.00 billion in non-convertible debt during the prior three-year period. References herein to "emerging growth company" shall have the meaning associated with it in the JOBS Act.

#### Foreign Private Issuer
Arqit is a "foreign private issuer" under SEC rules. Consequently, Arqit is subject to the reporting requirements under the Exchange Act applicable to foreign private issuers. Arqit will be required to file its annual reports on Form 20-F, and will furnish reports on Form 6-K to the SEC regarding certain information that is distributed or required to be distributed by Arqit to its shareholders.

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Based on its foreign private issuer status, Arqit will not be required to file periodic reports and financial statements with the SEC as frequently or as promptly as a U.S. company whose securities are registered under the Exchange Act. Arqit will also not be required to comply with Regulation FD, which addresses certain restrictions on the selective disclosure of material information. In addition, among other matters, Arqit officers, directors and principal shareholders will be exempt from the reporting and "short- swing" profit recovery provisions of Section 16 of the Exchange Act and the rules under the Exchange Act with respect to their purchases and sales of Ordinary Shares.

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#### THE OFFERING
Securities offered by the Selling Securityholders

We are registering the resale by the Selling Securityholders named in this prospectus, or their permitted transferees, of an aggregate of 11,514,816 Ordinary Shares (the "**Resale Shares**").

Ordinary Shares issuable upon the exercise of the Warrants

In addition, we are registering up to 5,440,000 Ordinary Shares issuable upon the exercise of the September 2024 Warrants.

Terms of the Offering

The Selling Securityholders will determine when and how they will dispose of the Resale Shares.

Ordinary Shares outstanding prior to the offering

As of September 18, 2025, we had 15,292,167 Ordinary Shares issued and outstanding.

Voting Rights

The Ordinary Shares each have one vote per share.

Use of proceeds

We will not receive any of the proceeds from the sale of the Resale Shares by the Selling Securityholders, except with respect to amounts received by us due to the cash exercise of the September 2023 Investor Warrants and September 2024 Warrants. If each outstanding September 2023 Investor Warrant and September 2024 Warrant is exercised for cash, we will receive aggregate cash proceeds of approximately $19.8 million. We expect to use the proceeds received from the exercise of the September 2023 Investor Warrants and September 2024 Warrants, if any, for general corporate purposes.

Dividend policy

We have not paid any cash dividends on our Ordinary Shares to date. Our board of directors will consider whether or not to institute a dividend policy. It is presently intended that we will retain our earnings for use in business operations and, accordingly, it is not anticipated that our board of directors will declare dividends in the foreseeable future.

Nasdaq ticker symbol

Our Ordinary Shares and Public Warrants are listed on Nasdaq under the symbols "ARQQ" and "ARQQW," respectively. Our outstanding warrants other than the Public Warrants are distinct from, and are not fungible with, our Public Warrants. Unlike the Public Warrants, there is no established trading market for our other outstanding warrants and we do not expect a market to develop. We do not intend to apply for a listing for any of our other outstanding warrants on any securities exchange or other nationally recognized trading system. Without an active trading market, the liquidity of our outstanding warrants other than the Public Warrants will be limited.

Risk factors

See the section entitled "Risk Factors" and the other information included in this prospectus for a discussion of factors you should consider before deciding to invest in our Ordinary Shares.

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#### RISK FACTORS
 *An investment in our securities involves a high degree of risk. Before making an investment decision, you should carefully consider all risk factors set forth in any applicable prospectus supplement and the documents incorporated by reference in this prospectus, including the factors discussed under the heading "Risk Factors" in our most recent annual report on Form 20-F or any updates in our current reports on Form 6-K, which may be amended, supplemented or superseded from time to time by the other reports we file with the SEC in the future or by information in the applicable prospectus supplement. See "Incorporation of Certain Documents by Reference." Our business, prospects, financial condition, or operating results could be harmed by any of the risks described, as well as other risks not known to us or that we consider immaterial as of the date of this prospectus. The trading price of our securities could decline due to any of these risks, and, as a result, you may lose all or part of your investment.* 

#### Risks Related to this Offering by the Selling Securityholders
 ***Sales of a substantial number of our Ordinary Shares in the public market by the Selling Securityholders and/or by our existing securityholders could cause the price of our Ordinary Shares to fall.***

The Selling Securityholders can sell, under this prospectus, up to 11,514,816 Ordinary Shares, constituting approximately 52.0% of our outstanding Ordinary Shares on a fully diluted basis (assuming and after giving effect to the issuance of 5,757,408 Ordinary Shares upon exercise of the September 2023 Investor Warrants and the September 2024 Warrants). Depending on the price, other securityholders may have paid significantly more than the Selling Securityholders for any Ordinary Shares they may have purchased in the open market based on variable market price. All the Resale Shares offered in this prospectus may be resold for so long as the registration statement, of which this prospectus forms a part, is available for use. The sale of all or a portion of the Resale Shares being offered in this prospectus could result in a significant decline in the public trading price of our securities. Despite such a decline in the public trading price, some of the Selling Securityholders may still experience a positive rate of return on the Resale Shares they purchased due to the price at which such Selling Securityholder initially purchased the Resale Shares.

In addition, the resale, or expected or potential resale, of a substantial number of shares of our Ordinary Shares in the public market, including the Ordinary Shares registered in this registration statement, could occur at any time. For example, the Company's Registration Statement on Form F-3 (File No. 333-259982) registers for resale up to 2,049,713 Ordinary Shares, constituting approximately 9.2% of our outstanding Ordinary Shares on a fully diluted basis, on behalf of the selling securityholders named therein. Additionally, we are not restricted from issuing additional ordinary shares from time to time. For example, we may issue additional ordinary shares to raise cash for future capital expenditures or for other purposes. We may also acquire interests in other companies by using a combination of cash and our ordinary shares or just our ordinary shares. We may also issue securities convertible into, exchangeable for or that represent the right to receive our ordinary shares. The Company's Registration Statement on Form F-3 (File No. 333-284343) registers the issuance by the Company of up to a maximum aggregate offering price of $150,000,000 of our ordinary shares, preference shares, debt securities and/or warrants from time to time in one or more offerings, and the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $75,000,000 of the registrant's ordinary shares that may be issued and sold from time to time under an At The Market Offering Agreement, dated January 17, 2025, with H.C. Wainwright & Co., LLC, as sales agent. Such sales, or the perception that such sales could occur, could adversely affect the market price for our Ordinary Shares and make it more difficult for you to sell your holdings at times and prices that you determine are appropriate. Furthermore, we expect that, because there is a large number of shares being registered pursuant to the registration statement of which this prospectus forms a part, the Selling Securityholders will continue to offer such securities covered thereby pursuant to this prospectus or pursuant to Rule 144 for a significant period of time, the precise duration of which cannot be predicted. Accordingly, the adverse market and price pressures resulting from an offering pursuant to the registration statement may continue for an extended period of time.

These sales, or the possibility that these sales may occur, also might make it more difficult for us to sell equity securities in the future at a time and at a price that we deem appropriate.

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 ***Certain existing securityholders purchased, or may purchase, our securities at a price below the current trading price of such securities, and may experience a positive rate of return based on the current trading price. Other investors may not experience a similar rate of return.***

Certain of our shareholders, including some of the Selling Securityholders, acquired, or may acquire, Ordinary Shares at prices below the current trading price of our Ordinary Shares and may experience a positive rate of return based on the current trading price.

This prospectus relates to the offer and resale from time to time by the Selling Securityholders of up to 11,514,816 Ordinary Shares. Depending on the price, the public securityholders may have paid significantly more than the selling securityholders for any Ordinary Shares they may have purchased in the open market based on variable market price.

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#### CAPITALIZATION
The following table sets forth our total capitalization as of March 31, 2025 on:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an actual basis; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an as adjusted basis, assuming the full cash exercise of the September 2023 Investor Warrants at an exercise price of $19.50 per share and of the September 2024 Warrants at an exercise price of $2.50 per share, and the receipt of gross proceeds by us of approximately $19.8 million and the corresponding issuance of 5,757,408 Ordinary Shares.

The information in this table should be read in conjunction with the financial statements and notes thereto and other financial information included in this prospectus, any prospectus supplement or incorporated by reference in this prospectus. Our historical results do not necessarily indicate our expected results for any future periods.

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| | | |
|:---|:---|:---|
| | **As of March 31, 2025**  | **As of March 31, 2025**  |
| **(USD in thousands)**  | **Actual <br> (unaudited)**  | **As Adjusted <br> (unaudited)**  |
| **Cash and cash equivalents**  | $**24781** | $**44570** |
| **Equity:** |  |  |
| Share capital  | 34 | 48 |
| Share premium  | 168234 | 188009 |
| Other reserves  | 166804 | 166804 |
| Foreign currency translation reserve  | (4919) | (4919) |
| Share-based payment reserve  | 35105 | 35105 |
| Retained earnings  | (349280) | (349280) |
| **Total Equity**  | **15978** | **35767** |
| **Non-Current Debt:** |  |  |
| Lease Liabilities  | 577 | 577 |
| Warrant Liabilities  | 2 | 2 |
| **Total Capitalization**  | $**16557** | $**36346** |

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#### USE OF PROCEEDS
All of the Resale Shares offered by the Selling Securityholders pursuant to this prospectus will be sold by the Selling Securityholders for their respective amounts. We will not receive any of the proceeds from these sales.

We will receive up to an aggregate of approximately $19.8 million from the exercise of the outstanding September 2023 Investor Warrants and September 2024 Warrants, assuming the exercise in full of all such warrants for cash. We expect to use the net proceeds from the exercise of the September 2023 Investor Warrants and September 2024 Warrants, if any, for general corporate purposes. Our management will have broad discretion over the use of proceeds from the exercise of the September 2023 Investor Warrants and September 2024 Warrants.

There is no assurance that the holders of the September 2023 Investor Warrants and September 2024 Warrants will elect to exercise any or all of the September 2023 Investor Warrants or the September 2024 Warrants. The September 2023 Investor Warrants can be exercised on a cashless basis. To the extent that the warrants are exercised on a "cashless basis," the amount of cash we would receive from the exercise of the warrants will decrease.

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#### DIVIDEND POLICY
We have not paid any cash dividends on our Ordinary Shares to date. Our board of directors will consider whether or not to institute a dividend policy. It is presently intended that we will retain our earnings for use in business operations and, accordingly, it is not anticipated that our board of directors will declare dividends in the foreseeable future.

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#### DESCRIPTION OF SECURITIES
The following description of the material terms of the Ordinary Shares of the Company includes a summary of specified provisions of the Articles. This description is qualified by reference to the Articles.

The Company is a Cayman Islands exempted company (company number 374857) and its affairs are governed by the Articles, the Cayman Companies Act and the common law of the Cayman Islands. The Company is authorized to issue 37,520,000 Ordinary Shares, $0.0025 par value each and 2,480,000 preference shares, $0.0025 par value each. The Company currently has only one class of issued Ordinary Shares, which have identical rights in all respects and rank equally with one another. As of September 18, 2025, there were 15,292,167 Ordinary Shares issued and outstanding, 521,556 whole Ordinary Shares underlying our Public Warrants, 300,002 Ordinary Shares underlying our February 2023 Investor Warrants, 22,001 Ordinary Shares underlying our February 2023 Placement Agent Warrants, 317,408 Ordinary Shares underlying our September 2023 Investor Warrants and 28,207 September 2023 Placement Agent Warrants, all of which are currently exercisable, and 5,440,000 Ordinary Shares underlying our September 2024 Warrants, 4,720,000 of which will become exercisable on September 30, 2025, and 720,000 of which will become exercisable on October 9, 2025.

#### Ordinary Shares
Holders of Ordinary Shares are entitled to one vote for each share held of record on all matters to be voted on by shareholders.

There is no cumulative voting with respect to the election of directors, with the result that the holders of more than 50% of the shares voted for the election of directors can elect all of the directors.

Holders of Ordinary Shares do not have any conversion, preemptive or other subscription rights and there is no sinking fund or redemption provisions applicable to the Ordinary Shares.

#### Dividends
Subject to the foregoing, the payment of cash dividends in the future, if any, will be at the discretion of the board of directors and will depend upon such factors as earnings levels, capital requirements, contractual restrictions, the Company's overall financial condition, available distributable reserves and any other factors deemed relevant by the board of directors.

#### Liquidation
On a winding-up or other return of capital, subject to any special rights attaching to any other class of shares, holders of Ordinary Shares will be entitled to participate in any surplus assets in proportion to their shareholdings.

#### Differences in Company Law
Cayman Islands companies are governed by the Cayman Companies Act. The Cayman Companies Act is modelled on English Law but does not follow recent English Law statutory enactments, and differs from laws applicable to United States corporations and their shareholders. Set forth below is a summary of the material differences between the provisions of the Cayman Companies Act applicable to the Company and the laws applicable to companies incorporated in the United States and their shareholders.

#### Mergers and Similar Arrangements
In certain circumstances, the Cayman Companies Act allows for mergers or consolidations between two Cayman Islands companies, or between a Cayman Islands exempted company and a company incorporated in another jurisdiction (*provided* that is facilitated by the laws of that other jurisdiction).

Where the merger or consolidation is between two Cayman Islands companies, the directors of each company must approve a written plan of merger or consolidation containing certain prescribed information. That plan or merger or consolidation must then be authorized by either (a) a special resolution (usually a

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majority of two thirds of the voting shares voted at a general meeting) of the shareholders of each company; and (b) such other authorization, if any, as may be specified in such constituent company's articles of association. No shareholder resolution is required for a merger between a parent company (i.e., a company that owns at least 90% of the issued shares of each class in a subsidiary company) and its subsidiary company.

The consent of each holder of a fixed or floating security interest of a constituent company must be obtained, unless the court waives such requirement. If the Registrar of Companies of the Cayman Islands is satisfied that the requirements of the Cayman Companies Act (which includes certain other formalities) have been complied with, the Registrar of Companies of the Cayman Islands will register the plan of merger or consolidation.

Where the merger or consolidation involves a foreign company, the procedure is similar, save that with respect to the foreign company, the directors of the Cayman Islands exempted company are required to make a declaration to the effect that, having made due enquiry, they are of the opinion that the requirements set out below have been met: (i) that the merger or consolidation is permitted or not prohibited by the constitutional documents of the foreign company and by the laws of the jurisdiction in which the foreign company is incorporated, and that those laws and any requirements of those constitutional documents have been or will be complied with; (ii) that no petition or other similar proceeding has been filed and remains outstanding or order made or resolution adopted to wind up or liquidate the foreign company in any jurisdictions; (iii) that no receiver, trustee, administrator or other similar person has been appointed in any jurisdiction and is acting in respect of the foreign company, its affairs or its property or any part thereof; and (iv) that no scheme, order, compromise or other similar arrangement has been entered into or made in any jurisdiction whereby the rights of creditors of the foreign company are and continue to be suspended or restricted.

Where the surviving company is the Cayman Islands exempted company, the directors of the Cayman Islands exempted company are further required to make a declaration to the effect that, having made due enquiry, they are of the opinion that the requirements set out below have been met: (i) that the foreign company is able to pay its debts as they fall due and that the merger or consolidated is bona fide and not intended to defraud unsecured creditors of the foreign company; (ii) that in respect of the transfer of any security interest granted by the foreign company to the surviving or consolidated company (a) consent or approval to the transfer has been obtained, released or waived; (b) the transfer is permitted by and has been approved in accordance with the constitutional documents of the foreign company; and (c) the laws of the jurisdiction of the foreign company with respect to the transfer have been or will be complied with; (iii) that the foreign company will, upon the merger or consolidation becoming effective, cease to be incorporated, registered or exist under the laws of the relevant foreign jurisdiction; and (iv) that there is no other reason why it would be against the public interest to permit the merger or consolidation.

Where the above procedures are adopted, the Cayman Companies Act provides for a right of dissenting shareholders to be paid a payment of the fair value of his shares upon their dissenting to the merger or consolidation if they follow a prescribed procedure. In essence, that procedure is as follows: (a) the shareholder must give his written objection to the merger or consolidation to the constituent company before the vote on the merger or consolidation, including a statement that the shareholder proposes to demand payment for his shares if the merger or consolidation is authorized by the vote; (b) within 20 days following the date on which the merger or consolidation is approved by the shareholders, the constituent company must give written notice to each shareholder who made a written objection; (c) a shareholder must within 20 days following receipt of such notice from the constituent company, give the constituent company a written notice of his intention to dissent including, among other details, a demand for payment of the fair value of his shares; (d) within seven days following the date of the expiration of the period set out in paragraph (b) above or seven days following the date on which the plan of merger or consolidation is filed, whichever is later, the constituent company, the surviving company or the consolidated company must make a written offer to each dissenting shareholder to purchase his shares at a price that the company determines is the fair value and if the company and the shareholder agree the price within 30 days following the date on which the offer was made, the company must pay the shareholder such amount; and (e) if the company and the shareholder fail to agree a price within such 30 day period, within 20 days following the date on which such 30 day period expires, the company (and any dissenting shareholder) must file a petition with the Cayman Islands courts to determine the fair value and such petition must be accompanied by a list of the names and addresses of the

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dissenting shareholders with whom agreements as to the fair value of their shares have not been reached by the company. At the hearing of that petition, the court has the power to determine the fair value of the shares together with a fair rate of interest, if any, to be paid by the company upon the amount determined to be the fair value. Any dissenting shareholder whose name appears on the list filed by the company may participate fully in all proceedings until the determination of fair value is reached. These rights of a dissenting shareholder are not available in certain circumstances, for example, to dissenters holding shares of any class in respect of which an open market exists on a recognized stock exchange or recognized interdealer quotation system at the relevant date or where the consideration for such shares to be contributed are shares of any company listed on a national securities exchange or shares of the surviving or consolidated company.

Moreover, Cayman Islands law has separate statutory provisions that facilitate the reconstruction or amalgamation of companies in certain circumstances, schemes of arrangement will generally be more suited for complex mergers or other transactions involving widely held companies, commonly referred to in the Cayman Islands as a "scheme of arrangement" which may be tantamount to a merger. In the event that a merger was sought pursuant to a scheme of arrangement (the procedures for which are more rigorous and take longer to complete than the procedures typically required to consummate a merger in the United States), the arrangement in question must be approved by a majority in number of each class of shareholders and creditors with whom the arrangement is to be made and who must in addition represent three-fourths in value of each such class of shareholders or creditors, as the case may be, that are present and voting either in person or by proxy at an annual general meeting, or extraordinary general meeting summoned for that purpose. The convening of the meetings and subsequently the terms of the arrangement must be sanctioned by the Cayman Islands courts. While a dissenting shareholder would have the right to express to the court the view that the transaction should not be approved, the court can be expected to approve the arrangement if it satisfies itself that:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • we are not proposing to act illegally or beyond the scope of our corporate authority and the statutory provisions as to majority vote have been complied with;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the shareholders have been fairly represented at the meeting in question;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the arrangement is such as a businessman would reasonably approve; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the arrangement is not one that would more properly be sanctioned under some other provision of the Cayman Companies Act or that would amount to a "fraud on the minority."

If a scheme of arrangement or takeover offer (as described below) is approved, any dissenting shareholder would have no rights comparable to appraisal rights (providing rights to receive payment in cash for the judicially determined value of the shares), which would otherwise ordinarily be available to dissenting shareholders of United States corporations.

#### Squeeze-out Provisions
When a takeover offer is made and accepted by holders of 90% of the shares to whom the offer relates within four months, the offeror may, within a two-month period, require the holders of the remaining shares to transfer such shares on the terms of the offer. An objection can be made to the Cayman Islands courts, but this is unlikely to succeed unless there is evidence of fraud, bad faith, collusion or inequitable treatment of the shareholders.

Further, transactions similar to a merger, reconstruction and/or an amalgamation may in some circumstances be achieved through means other than these statutory provisions, such as a share capital exchange, asset acquisition or control, or through contractual arrangements of an operating business.

#### Shareholders' Suits
Maples and Calder (Cayman) LLP, our Cayman Islands legal counsel, is not aware of any reported class action having been brought in a Cayman Islands court. Derivative actions have been brought in the Cayman Islands courts, and the Cayman Islands courts have confirmed the availability for such actions. In most cases, we will be the proper plaintiff in any claim based on a breach of duty owed to us, and a claim against (for example) our officers or directors usually may not be brought by a shareholder. However,

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based both on Cayman Islands authorities and on English authorities, which would in all likelihood be of persuasive authority and be applied by a court in the Cayman Islands, exceptions to the foregoing principle apply in circumstances in which:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • a company is acting, or proposing to act, illegally or beyond the scope of its authority;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the act complained of, although not beyond the scope of the authority, could be effected if duly authorized by more than the number of votes which have actually been obtained; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • those who control the company are perpetrating a "fraud on the minority."

A shareholder may have a direct right of action against us where the individual rights of that shareholder have been infringed or are about to be infringed.

#### Enforcement of Civil Liabilities
The Cayman Islands has a different body of securities laws as compared to the United States and provides less protection to investors. Additionally, Cayman Islands companies may not have standing to sue before the Federal courts of the United States.

We have been advised by Maples and Calder (Cayman) LLP, our Cayman Islands legal counsel, that the courts of the Cayman Islands are unlikely (i) to recognize or enforce against us judgments of courts of the United States predicated upon the civil liability provisions of the federal securities laws of the United States or any state; and (ii) in original actions brought in the Cayman Islands, to impose liabilities against us predicated upon the civil liability provisions of the federal securities laws of the United States or any state, so far as the liabilities imposed by those provisions are penal in nature. In those circumstances, although there is no statutory enforcement in the Cayman Islands of judgments obtained in the United States, the courts of the Cayman Islands will recognize and enforce a foreign money judgment of a foreign court of competent jurisdiction without retrial on the merits based on the principle that a judgment of a competent foreign court imposes upon the judgment debtor an obligation to pay the sum for which judgment has been given provided certain conditions are met. For a foreign judgment to be enforced in the Cayman Islands, such judgment must be final and conclusive and for a liquidated sum, and must not be in respect of taxes or a fine or penalty, inconsistent with a Cayman Islands judgment in respect of the same matter, impeachable on the grounds of fraud or obtained in a manner, and or be of a kind the enforcement of which is, contrary to natural justice or the public policy of the Cayman Islands (awards of punitive or multiple damages may well be held to be contrary to public policy). A Cayman Islands court may stay enforcement proceedings if concurrent proceedings are being brought elsewhere.

#### Special Considerations for Exempted Companies
We are an exempted company with limited liability under the Cayman Companies Act. The Cayman Companies Act distinguishes between ordinary resident companies and exempted companies. Any company that is registered in the Cayman Islands but conducts business mainly outside of the Cayman Islands may apply to be registered as an exempted company. The requirements for an exempted company are essentially the same as for an ordinary company except for the exemptions and privileges listed below:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an exempted company does not have to file an annual return of its shareholders with the Registrar of Companies of the Cayman Islands;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an exempted company's register of members is not open to inspection;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an exempted company does not have to hold an annual general meeting;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an exempted company may issue shares with no par value;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an exempted company may obtain an undertaking against the imposition of any future taxation (such undertakings are usually given for 20 years in the first instance);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an exempted company may register by way of continuation in another jurisdiction and be deregistered in the Cayman Islands;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an exempted company may register as a limited duration company; and

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an exempted company may register as a segregated portfolio company.

"*Limited liability*" means that the liability of each shareholder is limited to the amount unpaid by the shareholder on the shares of the company (except in exceptional circumstances, such as involving fraud, the establishment of an agency relationship or an illegal or improper purpose or other circumstances in which a court may be prepared to pierce or lift the corporate veil).

#### Indemnification of Directors and Executive Officers and Limitation of Liability
Cayman Islands law does not limit the extent to which a company's articles of association may provide for indemnification of officers and directors, except to the extent any such provision may be held by the Cayman Islands courts to be contrary to public policy, such as to provide indemnification against willful default, willful neglect, civil fraud or the consequences of committing a crime. The Articles permit indemnification of officers and directors for any liability, action, proceeding, claim, demand, costs damages or expenses, including legal expenses, incurred in their capacities as such unless such liability (if any) arises from actual fraud, willful neglect or willful default which may attach to such directors or officers. This standard of conduct is generally the same as permitted under the Delaware General Corporation Law for a Delaware corporation. In addition, we have entered into indemnification agreements with our directors and senior executive officers that provide such persons with additional indemnification beyond that provided in the Articles.

Insofar as indemnification for liabilities arising under the Securities Act may be permitted to our directors, officers or persons controlling us under the foregoing provisions, we have been informed that, in the opinion of the SEC, such indemnification is against public policy as expressed in the Securities Act and is therefore unenforceable.

#### Anti-Takeover Provisions in the Articles
Some provisions of the Articles may discourage, delay or prevent a change of control of our company or management that shareholders may consider favorable, including a provision that authorizes our board of directors to issue preference shares in one or more series and to designate the price, rights, preferences, privileges and restrictions of such preference shares without any further vote or action by our shareholders.

Such shares could be issued quickly with terms calculated to delay or prevent a change in control of our company or make removal of management more difficult. If our board of directors decides to issue these preference shares, the price of our Ordinary Shares may fall and the voting and other rights of the holders of our Ordinary Shares may be materially adversely affected.

However, under Cayman Islands law, our directors may only exercise the rights and powers granted to them under the Articles for a proper purpose and for what they believe in good faith to be in the best interests of our company.

#### Directors' Fiduciary Duties
Under Delaware corporate law, a director of a Delaware corporation has a fiduciary duty to the corporation and its shareholders. This duty has two components: the duty of care and the duty of loyalty. The duty of care requires that a director act in good faith, with the care that an ordinarily prudent person would exercise under similar circumstances. Under this duty, a director must inform himself or herself of, and disclose to shareholders, all material information reasonably available regarding a significant transaction. The duty of loyalty requires that a director act in a manner he or she reasonably believes to be in the best interests of the corporation. A director must not use his or her corporate position for personal gain or advantage. This duty prohibits self-dealing by a director and mandates that the best interest of the corporation and its shareholders take precedence over any interest possessed by a director, officer or controlling shareholder and not shared by the shareholders generally. In general, actions of a director are presumed to have been made on an informed basis, in good faith and in the honest belief that the action taken was in the best interests of the corporation. However, this presumption may be rebutted by evidence of a breach of one of the fiduciary duties. Should such evidence be presented concerning a transaction by a

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director, a director must prove the procedural fairness of the transaction, and that the transaction was of fair value to the corporation.

Under Cayman Islands law, directors and officers owe the following fiduciary duties:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • duty to act in good faith in what the director or officer believes to be in the best interests of the company as a whole;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • duty to exercise powers for the purposes for which those powers were conferred and not for a collateral purpose;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • directors should not improperly fetter the exercise of future discretion;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • duty to exercise powers fairly as between different sections of shareholders;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • duty not to put themselves in a position in which there is a conflict between their duty to the company and their personal interests; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • duty to exercise independent judgment.

In addition to the above, directors also owe a duty of care which is not fiduciary in nature. This duty has been defined as a requirement to act as a reasonably diligent person having both the general knowledge, skill and experience that may reasonably be expected of a person carrying out the same functions as are carried out by that director in relation to the company and the general knowledge skill and experience of that director.

As set out above, directors have a duty not to put themselves in a position of conflict and this includes a duty not to engage in self-dealing, or to otherwise benefit as a result of their position. However, in some instances what would otherwise be a breach of this duty can be forgiven and/or authorized in advance by the shareholders provided that there is full disclosure by the directors. This can be done by way of permission granted in the amended and restated memorandum and articles of association or alternatively by shareholder approval at general meetings.

#### Shareholder Action by Written Consent
Under the Delaware General Corporation Law, a corporation may eliminate the right of shareholders to act by written consent by amendment to its certificate of incorporation. The Articles provide that shareholders may approve corporate matters by way of a unanimous written resolution signed by or on behalf of each shareholder who would have been entitled to vote on such matter at a general meeting without a meeting being held.

#### Shareholder Proposals
Under the Delaware General Corporation Law, a shareholder has the right to put any proposal before the annual meeting of shareholders, provided it complies with the notice provisions in the governing documents. A special meeting may be called by the board of directors or any other person authorized to do so in the governing documents, but shareholders may be precluded from calling special meetings.

The Cayman Companies Act provides shareholders with only limited rights to requisition a general meeting, and does not provide shareholders with any right to put any proposal before a general meeting. However, these rights may be provided in a company's articles of association. The Articles do not permit our shareholders to requisition either an annual general meeting or an extraordinary general meeting, or to put forth a proposal at a general meeting. As a Cayman Islands exempted company, we are not obliged by law to call annual general meetings.

#### Cumulative Voting
Under the Delaware General Corporation Law, cumulative voting for elections of directors is not permitted unless the corporation's certificate of incorporation specifically provides for it. Cumulative voting potentially facilitates the representation of minority shareholders on a board of directors since it permits the minority shareholder to cast all the votes to which the shareholder is entitled on a single director, which

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increases the shareholder's voting power with respect to electing such director. As permitted under Cayman Islands law, the Articles do not provide for cumulative voting. As a result, our shareholders are not afforded any less protections or rights on this issue than shareholders of a Delaware corporation.

#### Removal of Directors
Under the Delaware General Corporation Law, a director of a corporation with a classified board may be removed only for cause with the approval of a majority of the issued and outstanding shares entitled to vote, unless the certificate of incorporation provides otherwise. Under the Articles, directors may be removed only for cause by a special resolution (usually a majority of two thirds of the voting shares voted at a general meeting) of our shareholders. A director will also cease to be a director if he or she (i) becomes bankrupt or makes any arrangement or composition with his creditors; (ii) dies or is found to be or becomes of unsound mind; (iii) resigns his office by notice in writing; (iv) the director absents himself or herself (for the avoidance of doubt, without being represented by proxy) from three consecutive meetings of the board of directors without special leave of absence from the directors, and the directors pass a resolution that he or she has by reason of such absence vacated office; or (v) all of the other directors (being not less than two in number) determine that he or she should be removed as a director for "Cause" (i.e., a conviction for a criminal offence involving dishonesty or engaging in conduct which brings a director or the Company into disrepute or which results in a material financial detriment to the Company) (and not otherwise), either by a resolution passed by all of the other directors at a meeting of the directors duly convened and held in accordance with the Articles or by a resolution in writing signed by all of the other directors.

#### Transactions with Interested Shareholders
The Delaware General Corporation Law contains a business combination statute applicable to Delaware corporations whereby, unless the corporation has specifically elected not to be governed by such statute under its certificate of incorporation, it is prohibited from engaging in certain business combinations with an "interested shareholder" for three years following the date that such person becomes an interested shareholder. An interested shareholder generally is a person or a group who or which owns or owned 15% or more of the target's outstanding voting stock within the past three years. This has the effect of limiting the ability of a potential acquirer to make a two-tiered bid for the target in which all shareholders would not be treated equally. The statute does not apply if, among other things, prior to the date on which such shareholder becomes an interested shareholder, the board of directors approves the transaction which resulted in the person becoming an interested shareholder. This encourages any potential acquirer of a Delaware corporation to negotiate the terms of any acquisition transaction with the target's board of directors.

Cayman Islands law has no comparable statute. As a result, we cannot avail ourselves of the types of protections afforded by the Delaware business combination statute. However, although Cayman Islands law does not regulate transactions between a company and its significant shareholders, it does provide that such transactions must be entered into bona fide in the best interests of the company and for a proper corporate purpose and not with the effect of constituting a fraud on the minority shareholders.

#### Dissolution; Winding Up
Under the Delaware General Corporation Law, unless the board of directors approves the proposal to dissolve, dissolution must be approved by shareholders holding 100% of the total voting power of the corporation. Only if the dissolution is initiated by the board of directors may it be approved by a simple majority of the corporation's outstanding shares. Delaware law allows a Delaware corporation to include in its certificate of incorporation a supermajority voting requirement in connection with dissolutions initiated by the board.

Under Cayman Islands law, a company may be wound up by either an order of the courts of the Cayman Islands or by a special resolution of its members or, if the company is unable to pay its debts as they fall due, by an ordinary resolution of its members. The court has authority to order winding up in a number of specified circumstances including where it is, in the opinion of the court, just and equitable to do so.

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Under the Articles, if the Company is wound up, the liquidator of our company may distribute the assets with the sanction of an ordinary resolution of the shareholders and any other sanction required by law.

#### Variation of Rights of Shares
Under the Delaware General Corporation Law, a corporation may vary the rights of a class of shares with the approval of a majority of the outstanding shares of such class, unless the certificate of incorporation provides otherwise.

Under the Articles, if our share capital is divided into more than one class of shares, the rights attached to any such class may, whether or not the Company is being wound up, be varied without the consent of the holders of the issued shares of that class where such variation is considered by the directors not to have a material adverse effect upon such rights; otherwise, any such variation shall be made only with the consent in writing of the holders of not less than two thirds of the issued shares of that class or with the approval of a resolution passed by a majority of not less than two thirds of the votes cast at a separate meeting of the holders of the shares of that class.

#### Amendment of Governing Documents
Under the Delaware General Corporation Law, a corporation's governing documents may be amended with the approval of a majority of the outstanding shares entitled to vote on the matter, unless the certificate of incorporation provides otherwise. As permitted by Cayman Islands law, the Articles may only be amended by a special resolution of the shareholders.

#### Rights of Non-Resident or Foreign Shareholders
There are no limitations imposed by the Articles on the rights of non-resident or foreign shareholders to hold or exercise voting rights on our shares. In addition, there are no provisions in the Articles governing the ownership threshold above which shareholder ownership must be disclosed.

#### Directors' Power to Issue Shares
Subject to applicable law, our board of directors is empowered to issue or allot shares or grant options and warrants with or without preferred, deferred, or other rights or restrictions.

#### Inspection of Books
Under the Delaware General Corporation Law, any shareholder of a corporation may for any proper purpose inspect or make copies of the corporation's stock ledger, list of shareholders and other books and records.

Holders of our shares have no general right under Cayman Islands law to inspect or obtain copies of our register of members or our corporate records.

#### Directors

#### Appointment and removal
The Directors are divided into three classes designated as Class I, Class II and Class III, respectively. Directors were assigned to each class in accordance with a resolution or resolutions adopted by the board of Directors. At the 2025 annual general meeting of the Company, the term of office of the Class I Directors shall expire and Class I Directors shall be elected for a full term of three years. At the 2026 annual general meeting of the Company, the term of office of the Class II Directors shall expire and Class II Directors shall be elected for a full term of three years. At the 2027 annual general meeting of the Company, the term of office of the Class III Directors shall expire and Class III Directors shall be elected for a full term of three years. At each succeeding annual general meeting of the Company, Directors shall be elected for a full term of three years to succeed the Directors of the class whose terms expire at such annual general meeting.

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Notwithstanding the foregoing provisions of this Article, each Director shall hold office until the expiration of his term, until his successor shall have been duly elected and qualified or until his earlier death, resignation or removal.

There is no cumulative voting with respect to the appointment of directors.

An ordinary resolution under Cayman Islands law, which requires the affirmative vote of a majority of the shareholders who attend and vote at a general meeting of the company, is required to elect a director.

The office of a Director shall be vacated if all of the other Directors (being not less than two in number) determine that he should be removed as a Director for Cause (and not otherwise) (as such term is defined in our amended and restated memorandum and articles of association), either by a resolution passed by all of the other Directors at a meeting of the Directors duly convened and held in accordance with the Articles or by a resolution in writing signed by all of the other Directors.

#### Enforceability of Civil Liability under Cayman Islands Law
The Company has been advised by Maples and Calder (Cayman) LLP, its Cayman Islands legal counsel, that the courts of the Cayman Islands are unlikely (i) to recognize, or enforce against the Company, judgments of courts of the United States predicated upon the civil liability provisions of the securities laws of the United States or any State; and (ii) in original actions brought in the Cayman Islands, to impose liabilities against the Company predicated upon the civil liability provisions of the securities laws of the United States or any State, so far as the liabilities imposed by those provisions are penal in nature. In those circumstances, although there is no statutory enforcement in the Cayman Islands of judgments obtained in the United States, the courts of the Cayman Islands will recognize and enforce a foreign money judgment of a foreign court of competent jurisdiction without retrial on the merits based on the principle that a judgment of a competent foreign court imposes upon the judgment debtor an obligation to pay the sum for which judgment has been given provided certain conditions are met. For a foreign judgment to be enforced in the Cayman Islands, such judgment must be final and conclusive and for a liquidated sum, and must not be in respect of taxes or a fine or penalty, inconsistent with a Cayman Islands judgment in respect of the same matter, impeachable on the grounds of fraud or obtained in a manner, and or be of a kind the enforcement of which is, contrary to natural justice or the public policy of the Cayman Islands (awards of punitive or multiple damages may well be held to be contrary to public policy). A Cayman Islands court may stay enforcement proceedings if concurrent proceedings are being brought elsewhere. There is recent Privy Council authority (which is binding on the Cayman Islands court) in the context of a reorganization plan approved by the New York Bankruptcy Court which suggests that due to the universal nature of bankruptcy/insolvency proceedings, foreign money judgments obtained in foreign bankruptcy/insolvency proceedings may be enforced without applying the principles outlined above. However, a more recent English Supreme Court authority (which is highly persuasive but not binding on the Cayman Islands court), has expressly rejected that approach in the context of a default judgment obtained in an adversary proceeding brought in the New York Bankruptcy Court by the receivers of the bankruptcy debtor against a third party, and which would not have been enforceable upon the application of the traditional common law principles summarized above and held that foreign money judgments obtained in bankruptcy/insolvency proceedings should be enforced by applying the principles set out above, and not by the simple exercise of the Courts' discretion. Those cases have now been considered by the Cayman Islands court. The Cayman Islands court was not asked to consider the specific question of whether a judgment of a bankruptcy court in an adversary proceeding would be enforceable in the Cayman Islands, but it did endorse the need for active assistance of overseas bankruptcy proceedings. We understand that the Cayman Islands court's decision in that case has been appealed and it remains the case that the law regarding the enforcement of bankruptcy/ insolvency related judgments is still in a state of uncertainty.

#### Anti-Money Laundering — Cayman Islands
If any person in the Cayman Islands knows or suspects or has reasonable grounds for knowing or suspecting that another person is engaged in criminal conduct or money laundering or is involved with terrorism or terrorist financing and property and the information for that knowledge or suspicion came to their attention in the course of business in the regulated sector, or other trade, profession, business or employment, the person will be required to report such knowledge or suspicion to (i) the Financial Reporting

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Authority of the Cayman Islands, pursuant to the Proceeds of Crime Law (2020 Revision) of the Cayman Islands if the disclosure relates to criminal conduct or money laundering, or (ii) a police officer of the rank of constable or higher, or the Financial Reporting Authority, pursuant to the Terrorism Law (2018 Revision) of the Cayman Islands, if the disclosure relates to involvement with terrorism or terrorist financing and property. Such a report shall not be treated as a breach of confidence or of any restriction upon the disclosure of information imposed by any enactment or otherwise.

#### Data Protection — Cayman Islands
We have certain duties under the Data Protection Act (As Revised) of the Cayman Islands (the "DPA") based on internationally accepted principles of data privacy.

#### Privacy Notice

#### Introduction
This privacy notice puts our shareholders on notice that through your investment in the Company you will provide us with certain personal information which constitutes personal data within the meaning of the DPA ("personal data"). In the following discussion, the "company" refers to us and our affiliates and/or delegates, except where the context requires otherwise.

#### Investor Data
We will collect, use, disclose, retain and secure personal data to the extent reasonably required only and within the parameters that could be reasonably expected during the normal course of business. We will only process, disclose, transfer or retain personal data to the extent legitimately required to conduct our activities of on an ongoing basis or to comply with legal and regulatory obligations to which we are subject. We will only transfer personal data in accordance with the requirements of the DPA, and will apply appropriate technical and organizational information security measures designed to protect against unauthorized or unlawful processing of the personal data and against the accidental loss, destruction or damage to the personal data.

In our use of this personal data, we will be characterized as a "data controller" for the purposes of the DPA, while our affiliates and service providers who may receive this personal data from us in the conduct of our activities may either act as our "data processors" for the purposes of the DPA or may process personal information for their own lawful purposes in connection with services provided to us.

We may also obtain personal data from other public sources. Personal data includes, without limitation, the following information relating to a shareholder and/or any individuals connected with a shareholder as an investor: name, residential address, email address, contact details, corporate contact information, signature, nationality, place of birth, date of birth, tax identification, credit history, correspondence records, passport number, bank account details, source of funds details and details relating to the shareholder's investment activity.

#### Who this Affects
If you are a natural person, this will affect you directly. If you are a corporate investor (including, for these purposes, legal arrangements such as trusts or exempted limited partnerships) that provides us with personal data on individuals connected to you for any reason in relation your investment in the company, this will be relevant for those individuals and you should transmit the content of this Privacy Notice to such individuals or otherwise advise them of its content.

#### How the Company May Use a Shareholder's Personal Data
The company, as the data controller, may collect, store and use personal data for lawful purposes, including, in particular:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • where this is necessary for the performance of our rights and obligations under any purchase agreements;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • where this is necessary for compliance with a legal and regulatory obligation to which we are subject (such as compliance with anti-money laundering and FATCA/CRS requirements); and/or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • where this is necessary for the purposes of our legitimate interests and such interests are not overridden by your interests, fundamental rights or freedoms.

Should we wish to use personal data for other specific purposes (including, if applicable, any purpose that requires your consent), we will contact you.

#### Why We May Transfer Your Personal Data
In certain circumstances we may be legally obliged to share personal data and other information with respect to your shareholding with the relevant regulatory authorities such as the Cayman Islands Monetary Authority or the Tax Information Authority. They, in turn, may exchange this information with foreign authorities, including tax authorities.

We anticipate disclosing personal data to persons who provide services to us and their respective affiliates (which may include certain entities located outside the United States, the Cayman Islands or the European Economic Area), who will process your personal data on our behalf.

#### The Data Protection Measures We Take
Any transfer of personal data by us or our duly authorized affiliates and/or delegates outside of the Cayman Islands shall be in accordance with the requirements of the DPA.

We and our duly authorized affiliates and/or delegates shall apply appropriate technical and organizational information security measures designed to protect against unauthorized or unlawful processing of personal data, and against accidental loss or destruction of, or damage to, personal data.

We shall notify you of any personal data breach that is reasonably likely to result in a risk to your interests, fundamental rights or freedoms or those data subjects to whom the relevant personal data relates.

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#### SELLING SECURITYHOLDERS
The Selling Securityholders may offer and sell, from time to time, any or all of the Resale Shares being offered for resale by this prospectus.

The term "Selling Securityholders" includes the securityholders listed in the table below and their permitted transferees.

The table below provides, as of the date of this prospectus, information regarding the beneficial ownership of our Ordinary Shares by each Selling Securityholder, the number of Resale Shares that may be sold by each Selling Securityholder under this prospectus and that each Selling Securityholder will beneficially own after this offering. Beneficial ownership percentages are based on 22,184,708 Ordinary Shares outstanding, including (i) 15,292,167 Ordinary Shares issued and outstanding as of September 18, 2025, (ii) 6,629,172 Ordinary Shares underlying our outstanding warrants that are currently exercisable or that will become exercisable within 60 days following September 18, 2025, and (iii) 263,369 shares underlying outstanding equity incentives that are exercisable or that will become exercisable within 60 days following September 18, 2025.

Because each Selling Securityholder may dispose of all, none or some portion of their securities, no estimate can be given as to the number of securities that will be beneficially owned by a Selling Securityholder upon termination of this offering. For purposes of the table below, however, we have assumed that after termination of this offering none of the securities covered by this prospectus will be beneficially owned by the Selling Securityholder and further assumed that the Selling Securityholders will not acquire beneficial ownership of any additional securities during the offering. In addition, the Selling Securityholders may have sold, transferred or otherwise disposed of, or may sell, transfer or otherwise dispose of, at any time and from time to time, our securities in transactions exempt from the registration requirements of the Securities Act after the date on which the information in the table is presented.

---

| | | | | | |
|:---|:---|:---|:---|:---|:---|
| | **Beneficial Ownership Prior to <br> the Offering**  | **Beneficial Ownership Prior to <br> the Offering**  | **Number of Resale <br> Shares Registered <br> for Sale Hereby**  | **Beneficial Ownership After <br> to the Offering**  | **Beneficial Ownership After <br> to the Offering**  |
| **Name**  | **Number**  | **Percent**  | **Number of Resale <br> Shares Registered <br> for Sale Hereby**  | **Number**  | **Percent**  |
| Heritage Assets SCSP<sup>(1)</sup>  | 10214252 | 46.0% | 9661540 | 552712 | 2.5% |
| Ropemakers Nominees Limited<sup>(2)</sup>  | 1870345 | 8.4% | 1352762 | 517583 | 2.3% |
| Carlo Calabria<sup>(3)</sup>  | 376235 | 1.7% | 260514 | 115721 | \* |
| Garth Ritchie<sup>(4)</sup>  | 263842 | 1.2% | 240000 | 23842 | \* |

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\*

Less than 1.0%.

(1) The business address for Heritage Assets SCSP is c/o Heritage Services SAM Attn: Cristina Levis, 7 Rue Du Gabian, 98000, Monaco. Beneficial ownership prior to the offering includes 86,591 shares underlying Public Warrants and 230,769 shares underlying September 2023 Investor Warrants that are currently exercisable, and 4,600,000 September 2024 Warrants that will become exercisable on September 30, 2025. Arqit director Manfredi Lefebvre d'Ovidio has shared investment and voting power over the shares held by Heritage Assets SCSP.

(2) The business address for Ropemaker Nominees Limited is 1st Floor, Royal Chambers, St Julian's Avenue, St Peter Port, Guernsey GY1 3JX. Notion Capital Managers LLP has sole investment and voting power over Ropemaker Nominees Limited's shares. The investment decisions of Notion Capital Managers LLP are made by the majority vote of an investment committee comprised of five members, including Arqit director Stephen Chandler. Under the so-called "rule of three," if voting and dispositive decisions regarding an entity's securities are made by three or more individuals, and a voting or dispositive decision requires the approval of at least a majority of those individuals, then none of the individuals is deemed a beneficial owner of the entity's securities. Based upon the foregoing analysis, no individual member of the investment committee of Notion Capital Managers LLP exercises voting or dispositive control over any of the securities over which it holds sole investment and voting power. Accordingly, Mr. Chandler is not deemed to have or share beneficial ownership of such shares. Beneficial ownership prior to the offering includes 76,381 shared underlying September 2023 Investor Warrants that are currently exercisable, and 600,000 September 2024 Warrants that will become exercisable on October 9, 2025.

(3) The business address of Carlo Calabria is 3 Orchard Place, London SW1H 0BF, United Kingdom. Beneficial ownership prior to the offering includes 10,256 shares underlying September 2023 Investor Warrants that are currently exercisable, 120,000 September 2024 Warrants that will become exercisable on October 9, 2025 and restricted share units that will vest within 60 days of September 18, 2025. Carlo Calabria is an Arqit director.

(4) The business address of Garth Ritchie is 3 Orchard Place, London SW1H 0BF, United Kingdom. Beneficial ownership prior to the offering includes 120,000 September 2024 Warrants that will become exercisable on September 30, 2025 and restricted share units that will vest within 60 days of September 18, 2025. Garth Ritchie is an Arqit director.

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#### TAX CONSIDERATIONS

#### Certain Material U.S. Federal Income Tax Considerations

#### General
The following discussion summarizes certain United States federal income tax considerations generally applicable to the acquisition, ownership and disposition of the Company's Ordinary Shares by U.S. Holders (as defined below) and Non-U.S. Holders (as defined below) that purchase the Ordinary Shares for cash pursuant to this prospectus. This discussion is limited to certain United States federal income tax considerations to beneficial owners of the Company's Ordinary Shares that will hold the such securities as "capital assets" within the meaning of Section 1221 of the U.S. Internal Revenue Code of 1986, as amended (the "Code") (generally, property held for investment). This discussion assumes that any distributions made (or deemed made) by the Company on the Company's Ordinary Shares and any consideration received (or deemed received) by a holder in consideration for the sale or other disposition of the Company's Ordinary Shares will be in U.S. dollars.

This discussion does not address the United States federal income tax consequences to the officers or directors of the Company. This discussion also does not address the U.S. federal income tax consequences of the exercise of any of the Company's warrants by existing holders of such warrants, and such holders should consult their own tax advisors regarding the U.S. federal income tax consequences to them of their receipt of Ordinary Shares in connection with an exercise of such warrants. This discussion is a summary only and does not describe all of the tax consequences that may be relevant to the acquisition, ownership and disposition of the Company's Ordinary Shares by a prospective investor in light of its particular circumstances, including but not limited to, the alternative minimum tax, the Medicare tax on net investment income and the different consequences that may apply to investors that are subject to special rules under U.S. federal income tax laws, including but not limited to:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • banks, financial institutions or financial services entities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • broker-dealers;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • taxpayers that are subject to the mark-to-market tax accounting rules;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • tax-exempt entities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • governments or agencies or instrumentalities thereof;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • insurance companies;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • regulated investment companies;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • real estate investment trusts;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • expatriates or former long-term residents of the United States;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • persons that actually or constructively own five percent or more (by vote or value) of the Company's shares;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • persons that acquired the Company's Ordinary Shares pursuant to an exercise of employee share options, in connection with employee share incentive plans or otherwise as compensation;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • persons that hold the Company's Ordinary Shares as part of a straddle, constructive sale, hedge, wash sale, conversion or other integrated or similar transaction;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • U.S. Holders (as defined below) whose functional currency is not the U.S. dollar;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • controlled foreign corporations;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • passive foreign investment companies; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • partnerships (or entities or arrangements classified as partnerships or other pass-through entities for U.S. federal income tax purposes) and any beneficial owners of such partnerships or other pass-through entities.

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If a partnership (or other entity or arrangement classified as a partnership or other pass-through entity for United States federal income tax purposes) is the beneficial owner of the Company's Ordinary Shares, the United States federal income tax treatment of a partner, member or other beneficial owner in such partnership or other pass-through entity generally will depend on the status of the partner, member or other beneficial owner and the activities of the partnership or other pass-through entity. Partnerships and other pass-through entities holding the Company's Ordinary Shares, as well as partners, members or other beneficial owners of such partnerships or other pass-through entities, are urged to consult their own tax advisors regarding the tax consequences of the acquisition, ownership and disposition of the Company's Ordinary Shares.

Moreover, the discussion below is based upon the provisions of the Code, the Treasury regulations promulgated thereunder and administrative and judicial interpretations thereof, all as of the date hereof, and such provisions may be repealed, revoked, modified or subject to differing interpretations, possibly on a retroactive basis, which may result in United States federal income tax consequences different from those discussed below. Furthermore, this discussion does not address any aspect of United States federal non- income tax laws, such as gift or estate tax laws, or state, local or non-United States tax laws.

The Company has not sought, and does not expect to seek, a ruling from the United States Internal Revenue Service ("IRS") as to any United States federal income tax consequence described herein. The IRS may disagree with the discussion herein, and its determination may be upheld by a court. Moreover, there can be no assurance that future legislation, regulations, administrative rulings or court decisions will not adversely affect the accuracy of the statements in this discussion.

THIS DISCUSSION IS ONLY A SUMMARY OF CERTAIN UNITED STATES FEDERAL INCOME TAX CONSIDERATIONS ASSOCIATED WITH THE ACQUISITION, OWNERSHIP AND DISPOSITION OF THE COMPANY'S ORDINARY SHARES. EACH PROSPECTIVE INVESTOR IN THE ORDINARY SHARES IS URGED TO CONSULT ITS OWN TAX ADVISOR WITH RESPECT TO THE PARTICULAR TAX CONSEQUENCES TO SUCH INVESTOR OF THE ACQUISITION, OWNERSHIP AND DISPOSITION OF THE ORDINARY SHARES, INCLUDING THE APPLICABILITY AND EFFECT OF ANY UNITED STATES FEDERAL, STATE, AND LOCAL, AND NON-UNITED STATES TAX LAWS.

#### U.S. Holders
This section applies to "U.S. Holders." A U.S. Holder is a beneficial owner of Ordinary Shares who or that is, for United States federal income tax purposes:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an individual who is a citizen or resident of the United States;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • a corporation (or other entity taxable as a corporation) organized in or under the laws of the United States, any state thereof or the District of Columbia;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an estate whose income is subject to United States federal income tax regardless of its source; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • a trust, if (i) a court within the United States is able to exercise primary supervision over the administration of the trust and one or more United States persons (as defined in the Code) have authority to control all substantial decisions of the trust or (ii) it has a valid election in effect under Treasury Regulations to be treated as a United States person.

 *Taxation of Distributions* 

Subject to the passive foreign investment company ("PFIC") rules discussed below, a U.S. Holder generally will be required to include in gross income as dividends in the year actually or constructively received by the U.S. Holder the amount of any distribution of cash or other property (other than certain distributions of the Company's shares or rights to acquire the Company's shares) paid on the Company's Ordinary Shares to the extent the distribution is paid out of the Company's current or accumulated earnings and profits (as determined under United States federal income tax principles). Distributions in excess of such earnings and profits generally will be applied against and reduce the U.S. Holder's basis in its Ordinary Shares (but not below zero) and, to the extent in excess of such basis, will be treated as gain from the sale

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or exchange of such Ordinary Shares (the treatment of which is described under "— *Gain or Loss on Sale or Other Taxable Disposition of Ordinary Shares*" below).

Dividends paid by the Company will be taxable to a corporate U.S. Holder at regular rates and will not be eligible for the dividends-received deduction generally allowed to domestic corporations in respect of dividends received from other domestic corporations. With respect to non-corporate U.S. Holders, dividends generally will be taxed as "qualified dividend income" at the lower applicable long-term capital gains rate (see "— *Gain or Loss on Sale or Other Taxable Disposition of Ordinary Shares*" below) only if the Ordinary Shares are readily tradable on an established securities market in the United States, certain holding period and at-risk requirements are met, the Company is not a PFIC at the time the dividend was paid or in the previous year, and certain other requirements are met. U.S. Holders should consult their tax advisors regarding the availability of such lower rate for any dividends paid with respect to the Ordinary Shares.

 *Gain or Loss on Sale or Other Taxable Disposition of Ordinary Shares* 

Subject to the PFIC rules discussed below, a U.S. Holder generally will recognize capital gain or loss on the sale or other taxable disposition of the Ordinary Shares. Any such capital gain or loss generally will be long-term capital gain or loss if the U.S. Holder's holding period for such Ordinary Shares exceeds one year. Long-term capital gain realized by a non-corporate U.S. Holder may be taxed at reduced rates of taxation. The deductibility of capital losses is subject to certain limitations.

The amount of gain or loss recognized by a U.S. Holder on a sale or other taxable disposition of the Ordinary Shares generally will be equal to the difference between (i) the sum of the amount of cash and the fair market value of any property received in such disposition of the Ordinary Shares and (ii) the U.S. Holder's adjusted tax basis in its Ordinary Shares so disposed of. A U.S. Holder's adjusted tax basis in its Ordinary Shares generally will equal the U.S. Holder's acquisition cost reduced by any prior distributions treated as a return of capital.

 *Passive Foreign Investment Company Rules* 

A foreign (i.e., non-U.S.) corporation will be classified as a PFIC for United States federal income tax purposes if either (i) at least 75% of its gross income in a taxable year, including its pro rata share of the gross income of any corporation in which it is considered to own at least 25% of the shares by value, is passive income or (ii) at least 50% of its assets in a taxable year (ordinarily determined based on fair market value and averaged quarterly over the year), including its pro rata share of the assets of any corporation in which it is considered to own at least 25% of the shares by value, are held for the production of, or produce, passive income. Passive income generally includes, among other things, dividends, interest, rents and royalties (other than rents or royalties derived from the active conduct of a trade or business) and gains from the disposition of assets giving rise to passive income. For purposes of the PFIC asset test, cash and other assets readily convertible into cash are considered passive assets, and the aggregate fair market value of the assets of a publicly traded non-U.S. corporation generally is treated as being equal to the sum of the aggregate value of the outstanding stock and the total amount of the liabilities of such corporation (the "Market Capitalization") and the excess of the fair market value of such corporation's assets as so determined over the book value of such assets is generally treated as goodwill that is a non-passive asset to the extent attributable to such corporation's non-passive income.

As of the date hereof, the Company has not made a determination as to its PFIC status for its most recent taxable year or its current taxable year. The Company's possible status as a PFIC is determined on an annual basis based on the composition of its assets, income, activities and Market Capitalization in the relevant taxable year and therefore may be subject to change. For example, because cash is generally considered to be an asset held for the production of passive income and the value of the Company's assets for purposes of the asset test will generally be determined based on the market price of the Company's Ordinary Shares, the Company's PFIC status will depend in large part on the market price of the Company's Ordinary Shares (which may fluctuate significantly) and how quickly the Company spends its cash in its operations. Accordingly, there can be no assurance that the Company is not a PFIC for any taxable year. In addition, the Company's U.S. counsel expresses no opinion with respect to the Company's PFIC status for any taxable year.

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Although the Company's PFIC status is determined annually, an initial determination that the Company is a PFIC generally will apply for subsequent years to a U.S. Holder who held Ordinary Shares while the Company is a PFIC, whether or not the Company meets the test for PFIC status in those subsequent years. If the Company is determined to be a PFIC for any taxable year (or portion thereof) that is included in the holding period of a U.S. Holder of the Ordinary Shares, and the U.S. Holder did not timely make either a mark-to-market election or a qualified electing fund ("QEF") election for the Company's first taxable year as a PFIC in which the U.S. Holder held (or was deemed to hold) Ordinary Shares, as described below, such U.S. Holder generally will be subject to special rules (such special rules, the "Default PFIC Regime") with respect to (i) any gain recognized by the U.S. Holder on the sale or other disposition of its Ordinary Shares (which may include gain realized by reason of transfers of Ordinary Shares that would otherwise qualify as nonrecognition transactions for U.S. federal income tax purposes) and (ii) any "excess distribution" made to the U.S. Holder (generally, any distributions to such U.S. Holder during a taxable year of the U.S. Holder that are greater than 125% of the average annual distributions received by such U.S. Holder in respect of the Ordinary Shares during the three preceding taxable years of such U.S. Holder or, if shorter, the portion of such U.S. Holder's holding period for the Ordinary Shares that preceded the taxable year of the distribution).

Under the Default PFIC Regime:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the U.S. Holder's gain or excess distribution will be allocated ratably over the U.S. Holder's holding period for the Ordinary Shares;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the amount allocated to the U.S. Holder's taxable year in which the U.S. Holder recognized the gain or received the excess distribution, or to the period in the U.S. Holder's holding period before the first day of the Company's first taxable year in which the Company is a PFIC, will be taxed as ordinary income;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the amount allocated to other taxable years (or portions thereof) of the U.S. Holder and included in its holding period will be taxed at the highest tax rate in effect for that year and applicable to the U.S. Holder without regard to the U.S. Holder's other items of income and loss for such year; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an additional amount equal to the interest charge generally applicable to underpayments of tax will be imposed on the U.S. Holder with respect to the tax attributable to each such other taxable year of the U.S. Holder.

In general, if the Company is determined to be a PFIC, a U.S. Holder may be able to avoid the Default PFIC Regime described above in respect to the Ordinary Shares by making a timely and valid QEF election (if eligible to do so) to include in income its pro rata share of the Company's net capital gains (as long-term capital gain) and other earnings and profits (as ordinary income), on a current basis, in each case whether or not distributed, in the taxable year of the U.S. Holder in which or with which the Company's taxable year ends. A U.S. Holder generally may make a separate election to defer the payment of taxes on undistributed income inclusions under the QEF rules, but if deferred, any such taxes will be subject to an interest charge.

If a U.S. Holder makes a QEF election with respect to its Ordinary Shares in a year after the Company's first taxable year as a PFIC in which the U.S. Holder held (or was deemed to hold) Ordinary Shares, then notwithstanding such QEF election, the Default PFIC Regime discussed above, adjusted to take into account the current income inclusions resulting from the QEF election, will continue to apply with respect to such U.S. Holder's Ordinary Shares, unless the U.S. Holder makes a purging election under the PFIC rules. Under one type of purging election, the U.S. Holder will be deemed to have sold such Ordinary Shares at their fair market value and any gain recognized on such deemed sale will be treated as an excess distribution, as described above. As a result of such purging election, the U.S. Holder will have additional basis (to the extent of any gain recognized on the deemed sale) and, solely for purposes of the PFIC rules, a new holding period in the Ordinary Shares.

The QEF election is made on a shareholder-by-shareholder basis and, once made, can be revoked only with the consent of the IRS. A U.S. Holder generally makes a QEF election by attaching a completed IRS Form 8621 (Information Return by a Shareholder of a Passive Foreign Investment Company or Qualified Electing Fund), including the information provided in a PFIC annual information statement, to a timely filed United States federal income tax return for the tax year to which the election relates. Retroactive QEF

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elections generally may be made only by filing a protective statement with such return and if certain other conditions are met or with the consent of the IRS. U.S. Holders should consult their tax advisors regarding the availability and tax consequences of a retroactive QEF election under their particular circumstances.

In order to comply with the requirements of a QEF election, a U.S. Holder must receive a PFIC annual information statement from the Company. There is no assurance, however, that the Company will have timely knowledge of its status as a PFIC in the future or that the Company will timely provide the required information for such years. The failure of the Company to provide such information on an annual basis could prevent a U.S. Holder from making a QEF election or result in the invalidation or termination of a U.S. Holder's prior QEF election.

If a U.S. Holder has made a QEF election with respect to its Ordinary Shares, and the Default PFIC Regime discussed above do not apply to such shares (because of a timely QEF election for the Company's first taxable year as a PFIC in which the U.S. Holder holds (or is deemed to hold) such shares or a purge of the PFIC taint pursuant to a purging election, as described above), any gain recognized on the sale of the Ordinary Shares generally will be taxable as capital gain and no additional interest charge will be imposed under the PFIC rules. As discussed above, if the Company is a PFIC for any taxable year, a U.S. Holder of Ordinary Shares that has made a QEF election will be currently taxed on its pro rata share of the Company's earnings and profits, whether or not distributed for such year. A subsequent distribution of such earnings and profits that were previously included in income generally should not be taxable when distributed to such U.S. Holder. The tax basis of a U.S. Holder's shares in a QEF will be increased by amounts that are included in income, and decreased by amounts distributed but not taxed as dividends, under the above rules. In addition, if the Company is not a PFIC for any taxable year, such U.S. Holder will not be subject to the QEF inclusion regime with respect to the Ordinary Shares for such a taxable year.

Alternatively, if a U.S. Holder, at the close of its taxable year, owns shares in a PFIC that are treated as marketable stock, the U.S. Holder may make a mark-to-market election with respect to such shares for such taxable year. If the U.S. Holder makes a valid mark-to-market election for the first taxable year of the U.S. Holder in which the U.S. Holder holds (or is deemed to hold) Ordinary Shares and for which the Company is determined to be a PFIC, such U.S. Holder generally will not be subject to the Default PFIC Regime described above with respect to its Ordinary Shares. Instead, in general, the U.S. Holder will include as ordinary income in each taxable year the excess, if any, of the fair market value of its Ordinary Shares at the end of its taxable year over its adjusted basis in its Ordinary Shares. These amounts of ordinary income would not be eligible for the favorable tax rates applicable to qualified dividend income or long-term capital gains. The U.S. Holder also will recognize an ordinary loss in respect of the excess, if any, of its adjusted basis in its Ordinary Shares over the fair market value of its Ordinary Shares at the end of its taxable year (but only to the extent of the net amount of previously included income as a result of the mark-to-market election). The U.S. Holder's basis in its Ordinary Shares will be adjusted to reflect any such income or loss amounts, and any further gain recognized on a sale or other taxable disposition of its Ordinary Shares will be treated as ordinary income and any further loss will be treated as ordinary loss (but only to the extent of the net amount of income previously included as a result of a mark-to-market election, and any loss in excess of such prior inclusions generally would be treated as capital loss). The mark-to-market election is available only for stock that is regularly traded on a national securities exchange that is registered with the Securities and Exchange Commission, including Nasdaq, or on a foreign exchange or market that the IRS determines has rules sufficient to ensure that the market price represents a legitimate and sound fair market value. If made, a mark-to-market election would be effective for the taxable year for which the election was made and for all subsequent taxable years unless the Ordinary Shares ceased to qualify as "marketable stock" for purposes of the PFIC rules or the IRS consented to the revocation of the election. U.S. Holders are urged to consult their own tax advisors regarding the availability and tax consequences of a mark-to-market election in respect to the Ordinary Shares under their particular circumstances.

The Company is a holding company which conducts its business activities through a non-U.S. subsidiary. If the Company is a PFIC and, at any time, have a non-U.S. subsidiary that is classified as a PFIC, U.S. Holders generally would be deemed to own a portion of the shares of such lower-tier PFIC, and generally could incur liability for the deferred tax and interest charge under the Default PFIC Regime described above if the Company receives a distribution from, or dispose of all or part of the Company's interest in, the lower-tier PFIC or the U.S. Holders otherwise were deemed to have disposed of an interest in the lower-tier

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PFIC. A mark-to-market election generally would not be available with respect to such lower-tier PFIC. U.S. Holders are urged to consult their tax advisors regarding the tax issues raised by lower-tier PFICs.

A U.S. Holder that owns (or is deemed to own) shares in a PFIC during any taxable year of the U.S. Holder, may have to file an IRS Form 8621 (whether or not a QEF or mark-to-market election is made) and such other information as may be required by the U.S. Treasury Department. Failure to do so, if required, will extend the statute of limitations until such required information is furnished to the IRS.

The rules dealing with PFICs and with the QEF, purging, and mark-to-market elections are very complex and are affected by various factors in addition to those described above. Accordingly, U.S. Holders of the Ordinary Shares should consult their own tax advisors concerning the application of the PFIC rules to the Ordinary Shares under their particular circumstances.

 *Tax Reporting* 

Certain U.S. Holders who are individuals and certain entities will be required to report information with respect to such U.S. Holder's investment in "specified foreign financial assets" on IRS Form 8938 (Statement of Specified Foreign Financial Assets), subject to certain exceptions. Specified foreign financial assets generally include any financial account maintained with a non-U.S. financial institution and should also include the Company's Ordinary Shares if they are not held in an account maintained with a U.S. financial institution. Persons who are required to report specified foreign financial assets and fail to do so may be subject to substantial penalties, and the period of limitations on assessment and collection of United States federal income taxes may be extended in the event of a failure to comply. Potential investors are urged to consult their tax advisors regarding the foreign financial asset and other reporting obligations and their application to an investment in the Company's Ordinary Shares.

#### Non-U.S. Holders
This section applies to "Non-U.S. Holders." As used herein, the term "Non-U.S. Holder" means a beneficial owner of the Ordinary Shares that is for United States federal income tax purposes:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • a non-resident alien individual (other than certain former citizens and residents of the United States subject to U.S. tax as expatriates);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • a foreign corporation; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an estate or trust that is not a U.S. Holder;

but generally does not include an individual who is present in the United States for 183 days or more in the taxable year of the disposition of the Ordinary Shares. Any such individual investor should consult its own tax advisor regarding the United States federal income tax consequences of the acquisition, ownership and disposition of the Company's Ordinary Shares.

Dividends paid or deemed paid to a Non-U.S. Holder in respect of the Company's Ordinary Shares generally will not be subject to United States federal income tax, unless the dividends are effectively connected with the Non-U.S. Holder's conduct of a trade or business within the United States (and, if required by an applicable income tax treaty, are attributable to a permanent establishment or fixed base that such Non-U.S. Holder maintains in the United States). In addition, a Non-U.S. Holder generally will not be subject to United States federal income tax on any gain attributable to a sale or other disposition of the Ordinary Shares unless such gain is effectively connected with its conduct of a trade or business in the United States (and, if required by an applicable income tax treaty, is attributable to a permanent establishment or fixed base that such Non-U.S. Holder maintains in the United States).

Dividends and gains that are effectively connected with the Non-U.S. Holder's conduct of a trade or business in the United States (and, if required by an applicable income tax treaty, are attributable to a permanent establishment or fixed base in the United States) generally will be subject to United States federal income tax at the same regular United States federal income tax rates applicable to a comparable U.S. Holder and, in the case of a Non-U.S. Holder that is a corporation for United States federal income tax purposes, also may be subject to an additional branch profits tax at a 30% rate or a lower applicable tax treaty rate.

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Non-U.S. Holders should consult their tax advisors regarding potentially applicable income tax treaties that may provide for different rules.

#### Information Reporting and Backup Withholding
Dividend payments with respect to the Ordinary Shares and proceeds from the sale, exchange or redemption of, the Ordinary Shares may be subject to information reporting to the IRS and possible United States backup withholding. Backup withholding will not apply, however, to a U.S. Holder who furnishes a correct taxpayer identification number and makes other required certifications, or who is otherwise exempt from backup withholding and establishes such exempt status. A Non-U.S. Holder generally will eliminate the requirement for information reporting and backup withholding by providing certification of its foreign status, under penalties of perjury, on a duly executed applicable IRS Form W-8 or by otherwise establishing an exemption.

Backup withholding is not an additional tax. Amounts withheld as backup withholding may be credited against a holder's United States federal income tax liability, and a holder generally may obtain a refund of any excess amounts withheld under the backup withholding rules by timely filing the appropriate claim for refund with the IRS and furnishing any required information.

#### Cayman Islands Tax Considerations
The following is a discussion on certain Cayman Islands income tax consequences of an investment in the securities of the company. The discussion is a general summary of present law, which is subject to prospective and retroactive change. It is not intended as tax advice, does not consider any investor's particular circumstances and does not consider tax consequences other than those arising under Cayman Islands law.

Under existing Cayman Islands Laws, payments of dividends and capital in respect of our securities will not be subject to taxation in the Cayman Islands and no withholding will be required on the payment of a dividend or capital to any holder of the securities nor will gains derived from the disposal of the securities be subject to Cayman Islands income or corporate tax. The Cayman Islands currently has no income, corporate or capital gains tax and no estate duty, inheritance tax or gift tax.

No stamp duty is payable in respect of the issue of our Ordinary Shares or on an instrument of transfer in respect of such shares.

The Company has been incorporated under the laws of the Cayman Islands as an exempted company with limited liability and, as such, has applied for and received an undertaking from the Financial Secretary of the Cayman Islands in the following form:

#### The Tax Concessions Law

#### Undertaking as to Tax

#### Concessions
In accordance with the Tax Concessions Law, the following undertaking is hereby given to Arqit Quantum Inc. (the "Company"):

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 1.

That no law which is hereafter enacted in the Islands imposing any tax to be levied on profits, income, gains or appreciations shall apply to the company or its operations; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 2.

In addition, that no tax to be levied on profits, income, gains or appreciations or which is in the nature of estate duty or inheritance tax shall be payable:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 2.1

on or in respect of the shares, debentures or other obligations of the company; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 2.2

by way of the withholding in whole or part, of any relevant payment as defined in the Tax Concessions Law.

These concessions shall be for a period of twenty years from the 28<sup>th</sup> day of April 2021.

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#### PLAN OF DISTRIBUTION
The Selling Securityholders which, as used here, includes donees, pledgees, transferees or other successors- in-interest selling Resale Shares or interests in Resale Shares received after the date of this prospectus from a Selling Securityholder as a gift, pledge, partnership distribution or other transfer, may, from time to time, sell, transfer or otherwise dispose of any or all of their Resale Shares or interests in the Resale Shares on any stock exchange, market or trading facility on which the shares are traded or in private transactions. These dispositions may be at fixed prices, at prevailing market prices at the time of sale, at prices related to the prevailing market price, at varying prices determined at the time of sale, or at negotiated prices.

The Selling Securityholders may use any one or more of the following methods when disposing of Resale Shares or interests therein:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • ordinary brokerage transactions and transactions in which the broker-dealer solicits purchasers;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • block trades in which the broker-dealer will attempt to sell the shares as agent, but may position and resell a portion of the block as principal to facilitate the transaction;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • purchases by a broker-dealer as principal and resale by the broker-dealer for their account;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an exchange distribution in accordance with the rules of the applicable exchange;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • privately negotiated transactions;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • short sales effected after the date the registration statement of which this prospectus is a part is declared effective by the SEC;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • through the writing or settlement of options or other hedging transactions, whether through an options exchange or otherwise;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • broker-dealers may agree with the Selling Securityholders to sell a specified number of such shares at a stipulated price per share;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • a combination of any such methods of sale; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • any other method permitted by applicable law.

The Selling Securityholders may, from time to time, pledge or grant a security interest in some or all of the Resale Shares owned by them and, if they default in the performance of their secured obligations, the pledgees or secured parties may offer and sell the Resale Shares, from time to time, under this prospectus, or under an amendment to this prospectus under Rule 424(b)(3) or other applicable provision of the Securities Act amending the list of Selling Securityholders to include the pledgee, transferee or other successors in interest as Selling Securityholders under this prospectus. The Selling Securityholders also may transfer the Resale Shares in other circumstances, in which case the transferees, pledgees or other successors in interest will be the selling beneficial owners for purposes of this prospectus.

In connection with the sale of the Resale Shares or interests therein, the Selling Securityholders may enter into hedging transactions with broker-dealers or other financial institutions, which may in turn engage in short sales of the Resale Shares in the course of hedging the positions they assume. The Selling Securityholders may also sell Resale Shares short and deliver these securities to close out their short positions, or loan or pledge the Resale Shares to broker-dealers that in turn may sell these securities. The Selling Securityholders may also enter into option or other transactions with broker-dealers or other financial institutions or the creation of one or more derivative securities which require the delivery to such broker-dealer or other financial institution of Resale Shares offered by this prospectus, which Resale Shares such broker-dealer or other financial institution may resell pursuant to this prospectus (as supplemented or amended to reflect such transaction).

Each of the Selling Securityholders reserves the right to accept and, together with their agents from time to time, to reject, in whole or in part, any proposed purchase of Resale Shares to be made directly or through agents. We will not receive any of the proceeds from this offering. Upon any exercise of the September 2023 Investor Warrants or September 2024 Warrants by payment of cash, however, we will receive the exercise price of the warrants.

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The Selling Securityholders and any underwriters, broker-dealers or agents that participate in the sale of the Resale Shares or interests therein may be "underwriters" within the meaning of Section 2(11) of the Securities Act.

Any discounts, commissions, concessions or profit they earn on any resale of the shares may be underwriting discounts and commissions under the Securities Act. Selling securityholders who are "underwriters" within the meaning of Section 2(11) of the Securities Act will be subject to the prospectus delivery requirements of the Securities Act.

In addition, a Selling Securityholder that is an entity may elect to make a pro rata in-kind distribution of securities to its members, partners or stockholders pursuant to the registration statement of which this prospectus is a part by delivering a prospectus with a plan of distribution. Such members, partners or stockholders would thereby receive freely tradeable securities pursuant to the distribution through a registration statement. To the extent a distributee is an affiliate of ours (or to the extent otherwise required by law), we may file a prospectus supplement in order to permit the distributees to use the prospectus to resell the securities acquired in the distribution.

To the extent required, the Resale Shares to be sold, the names of the Selling Securityholders, the respective purchase prices and public offering prices, the names of any agents, dealer or underwriter, any applicable commissions or discounts with respect to a particular offer will be set forth in an accompanying prospectus supplement or, if appropriate, a post-effective amendment to the registration statement that includes this prospectus.

In order to comply with the securities laws of some states, if applicable, the Resale Shares may be sold in these jurisdictions only through registered or licensed brokers or dealers. In addition, in some states the Resale Shares may not be sold unless they have been registered or qualified for sale or an exemption from registration or qualification requirements is available and is complied with.

We have advised the Selling Securityholders that the anti-manipulation rules of Regulation M under the Exchange Act may apply to sales of Resale Shares in the market and to the activities of the Selling Securityholders and their affiliates. In addition, to the extent applicable we will make copies of this prospectus (as it may be supplemented or amended from time to time) available to the Selling Securityholders for the purpose of satisfying the prospectus delivery requirements of the Securities Act. The Selling Securityholders may indemnify any broker-dealer that participates in transactions involving the sale of the shares against certain liabilities, including liabilities arising under the Securities Act.

We have agreed to indemnify the Selling Securityholders against liabilities, including liabilities under the Securities Act and state securities laws, relating to the registration of the Resale Shares offered by this prospectus.

We have agreed with the Selling Securityholders to keep the registration statement of which this prospectus constitutes a part effective until all of the shares covered by this prospectus have been disposed of pursuant to and in accordance with the registration statement or the securities have been withdrawn.

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#### EXPENSES RELATED TO THE OFFERING
Set forth below is an itemization of the total expenses that are expected to be incurred by us in connection with the offer and sale of the Ordinary Shares by the Selling Securityholders. With the exception of the SEC registration fee, all amounts are estimates.

---

| | |
|:---|:---|
| | **U.S. Dollar**  |
| SEC Registration Fee  | $77055.80 |
| Legal Fees and Expenses  | 75000.00 |
| Accounting Fees and Expenses  | 2000.00 |
| Printing Expenses  | 10000.00 |
| Miscellaneous Expenses  | 5000.00 |
| Total  | $169055.80 |

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#### LEGAL MATTERS
The validity of the Ordinary Shares offered by this prospectus has been passed upon by Maples and Calder (Cayman) LLP.

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#### EXPERTS
The financial statements of Arqit Quantum Inc. as of and for the years ended September 30, 2024, 2023 and 2022 incorporated in this prospectus by reference to the Annual Report on Form 20-F for the year ended September 30, 2024 have been so incorporated in reliance upon the report of PKF Littlejohn LLP, an independent registered public accounting firm appearing elsewhere herein, and upon the authority of said firm as experts in accounting and auditing.

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#### WHERE YOU CAN FIND MORE INFORMATION
We have filed a Form F-3 registration statement under the Securities Act of 1933, as amended, with respect to the Ordinary Shares offered by this prospectus. This prospectus does not contain all of the information included in the registration statement. For further information pertaining to us and our securities, you should refer to the registration statement and our exhibits.

We are subject to the informational requirements of the Exchange Act applicable to foreign private issuers. Accordingly, we will be required to file reports and other information with the SEC, including annual reports on Form 20-F and reports on Form 6-K. The SEC maintains an internet website that contains reports and other information about issuers, like us, that file electronically with the SEC. The address of that website is *www.sec.gov*.

As a foreign private issuer, we are exempt under the Exchange Act from, among other things, the rules prescribing the furnishing and content of proxy statements, and our officers, directors and principal shareholders are exempt from the reporting and short-swing profit recovery provisions contained in Section 16 of the Exchange Act with respect to their purchase and sale of our Ordinary Shares. In addition, we will not be required under the Exchange Act to file periodic reports and financial statements with the SEC as frequently or as promptly as U.S. companies whose securities are registered under the Exchange Act.

We will send our transfer agent a copy of all notices of shareholders' meetings and other reports, communications and information that are made generally available to shareholders. The transfer agent has agreed to mail to all shareholders a notice containing the information (or a summary of the information) contained in any notice of a meeting of our shareholders received by the transfer agent and will make available to all shareholders such notices and all such other reports and communications received by the transfer agent.

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#### INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE
The SEC allows the Company to "incorporate by reference" into this prospectus the information we file with or furnish to the SEC, which means that the Company can disclose important information to you by referring you to those documents. The Company hereby incorporates by reference in this prospectus the documents listed below and all amendments or supplements we may file to such documents:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our annual report on [Form 20-F](http://www.sec.gov/ix?doc=/Archives/edgar/data/1859690/000155837024016028/arqq-20240930x20f.htm) filed with the SEC on December 5, 2024;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our reports on [Form 6-K](https://www.sec.gov/Archives/edgar/data/1859690/000110465925032020/tm2511463d1_6k.htm), filed with the SEC on April 4, 2025, September 11, 2025 and September 16, 2025;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • exhibits [99.2](http://www.sec.gov/ix?doc=/Archives/edgar/data/1859690/000110465925051848/arqq-20250522xex99d2.htm) and [99.3](http://www.sec.gov/Archives/edgar/data/1859690/000110465925051848/arqq-20250522xex99d3.htm) to our report on Form 6-K, filed with the SEC on May 22, 2025; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the description of the securities contained in our registration statement on [Form 8-A](http://www.sec.gov/Archives/edgar/data/1859690/000110465921112042/tm2126804d1_8a12b.htm) filed on September 1, 2021 pursuant to Section 12 of the Exchange Act, together with all amendments and reports filed for the purpose of updating that description.

All documents subsequently filed by the Company pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act and, to the extent specifically designated therein, reports of foreign private issuer on Form 6-K furnished by the Company to the SEC, in each case, after the date of the initial registration statement of which this prospectus is a part and prior to the effectiveness of the registration statement, as well as prior to the completion or termination of the offering of securities under this prospectus, shall be deemed to be incorporated by reference in this prospectus and to be a part hereof from the date of filing or furnishing of such documents.

Any statement contained herein or in a document, all or a portion of which is incorporated or deemed to be incorporated by reference herein, shall be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained herein or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus.

Notwithstanding the foregoing, no information is incorporated by reference in this prospectus or any prospectus supplement hereto where such information under applicable forms and regulations of the SEC is not deemed to be "filed" under Section 18 of the Exchange Act or otherwise subject to the liabilities of that section, unless the report or filing containing such information indicates that the information therein is to be considered "filed" under the Exchange Act or is to be incorporated by reference in this prospectus or any prospectus supplement hereto.

We will provide to each person, including any beneficial owner, to whom this prospectus is delivered, a copy of any or all the reports or documents incorporated by reference in this prospectus, at no cost to the requester, upon written or oral request to us at the following address: Arqit Quantum Inc., 1st Floor, 3 Orchard Place, London SW1H 0BF, United Kingdom.

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