As of November 9, 2026, 2 holders' latest Schedule 13D or 13G filings report owning 5% or more of Arqit Quantum Inc. The largest reported stake is Heritage Assets SCSp's, at 38.6%. 7 filings are on record since August 26, 2025 (Schedule 13D/A, May 26, 2026).
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Key facts
- · Reporting person: Notion Capital III LP · Sole voting: 0 · Shared voting: 1,812,206 · Sole dispositive: 0 · Shared dispositive: 1,812,206 · SCHEDULE 13G/A, 2026-09-10
- · Reporting person: ICS Opportunities, Ltd. · Sole voting: 0 · Shared voting: 7,800 · Sole dispositive: 0 · Shared dispositive: 7,800 · SCHEDULE 13G, 2026-06-23
- · Holder: Heritage Assets SCSp · Percent: 38.6% · SCHEDULE 13D/A
- · Holder: Heritage Assets SCSp · Percent: 41.8% · SCHEDULE 13D/A
- · Holder: Heritage Assets SCSp · Percent: 43.2% · SCHEDULE 13D/A
Arqit Quantum Inc. has 7 Schedule 13D or 13G filings on record since 2025-08-26. 2 holders' latest filing reports 5% or more of ordinary shares. Each figure below is the holder's own, as filed, with the filing linked.
Holders
| Holder | Percent | Shares | Latest | Event date |
|---|---|---|---|---|
| Heritage Assets SCSp | 38.6% | 9,249,964 | SCHEDULE 13D/A, 2026-05-26 | 2026-05-21 |
| Notion Capital III LP | 10% | 1,812,206 | SCHEDULE 13G/A, 2026-09-10 | 2026-06-26 |
| Millennium Management LLC | 0.3% | 58,621 | SCHEDULE 13G, 2026-06-23 | 2026-06-16 |
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More on Arqit Quantum Inc. and the records around it.
Arqit Quantum Inc. elsewhere on the record
Companies that share a holder
- ICS Opportunities, Ltd. also filed stake reports on 2 other companies: Horizon Quantum Holdings Ltd. (Jun 2026)
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Voting and dispositive power, as filed
| Reporting person | Sole voting | Shared voting | Sole dispositive | Shared dispositive | Filing |
|---|---|---|---|---|---|
| Notion Capital III LP | 0 | 1,812,206 | 0 | 1,812,206 | SCHEDULE 13G/A, 2026-09-10 |
| ICS Opportunities, Ltd. | 0 | 7,800 | 0 | 7,800 | SCHEDULE 13G, 2026-06-23 |
| Millennium Management LLC | 0 | 58,621 | 0 | 58,621 | SCHEDULE 13G, 2026-06-23 |
| Millennium Group Management LLC | 0 | 58,621 | 0 | 58,621 | SCHEDULE 13G, 2026-06-23 |
| Israel A. Englander | 0 | 58,621 | 0 | 58,621 | SCHEDULE 13G, 2026-06-23 |
The latest filing identifies Arqit Quantum Inc. by CUSIP G0567U127 and gives its principal executive office as 3 Orchard Place, London (SCHEDULE 13G/A, 2026-09-10).
Purpose of Transaction (Item 4)
Heritage Assets SCSp
Item 4 of the Schedule 13D is amended by adding the following information: This Amendment No. 9 is being filed to update the aggregate number of Ordinary Shares and percentage of Ordinary Shares of Arqit beneficially owned by the Reporting Persons due to the dilution caused by Arqit's issuance of additional Ordinary Shares from time to time since the date of the filing of Amendment No. 8 to Schedule 13D by the Reporting Persons on November 12, 2025 ("Amendment No. 8"), which resulted in a decrease of over one percent (1%) in the aggregate percentage ownership reported by the Reporting Persons in Amendment No. 8. In addition, this Amendment No. 9 contains information regarding the sale by the Reporting Persons of Business Combination Warrants (as defined in Arqit's Annual Report on Form 20-F for the fiscal year ended September 30, 2025, filed with the Securities and Exchange Commission (the "SEC") on December 9, 2025) on a post-Reverse Stock Split basis at the average prices set forth in the table below, in each case in open market transactions, since the information contained in Amendment No. 8. Date of Transaction Amount of Business Average Price per Combination Warrants Business Combination Warrant ($) 11/11/2025 445 9.20 11/12/2025 290 …The first part of Item 4 of the SCHEDULE 13D/A filed 2026-05-26; the filing has the rest
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-08-26 | Heritage Assets SCSp | 49.6% | SCHEDULE 13D/A |
| 2025-09-24 | Heritage Assets SCSp | 46% | SCHEDULE 13D/A |
| 2025-10-20 | Heritage Assets SCSp | 43.2% | SCHEDULE 13D/A |
| 2025-11-12 | Heritage Assets SCSp | 41.8% | SCHEDULE 13D/A |
| 2026-05-26 | Heritage Assets SCSp | 38.6% | SCHEDULE 13D/A |
| 2026-06-23 | Millennium Management LLC | 0.3% | SCHEDULE 13G |
| 2026-09-10 | Notion Capital III LP | 10% | SCHEDULE 13G/A |
Questions about who owns Arqit Quantum Inc.
Who owns Arqit Quantum Inc.?
On this page, 2 holders' latest ownership filings report 5% or more of Arqit Quantum Inc.: Heritage Assets SCSp (38.6%, Schedule 13D/A, filed 2026-05-26) and Notion Capital III LP (10%, Schedule 13G/A, filed 2026-09-10).
Who are the largest shareholders of Arqit Quantum Inc.?
By the share each holder's latest filing reports, the largest holders of Arqit Quantum Inc. on this page are Heritage Assets SCSp (38.6%) and Notion Capital III LP (10%).
When did Heritage Assets SCSp buy into Arqit Quantum Inc.?
The filings give report dates, not purchase dates. The earliest filing from Heritage Assets SCSp on this page is the Schedule 13D/A, filed 2025-08-26, reporting 49.6%; its latest, Schedule 13D/A filed 2026-05-26, reports 38.6%. That earliest filing is itself an amendment, which updates an earlier report.
Is this an audit or a full list?
Neither. The ownership list on this page covers only Schedule 13D and 13G filings, which holders make once they own 5% or more of a class of shares (an amendment can report a stake that has since fallen below 5%); 7 such filings are shown here. It is not an audit and not a full cap table: holders who never reached 5% are not listed, and a stake can change after its latest filing.
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Where this comes from
Anyone who comes to own more than 5% of a class of a listed company's voting shares has to tell the SEC. A holder who may seek to change or influence the company files Schedule 13D, and has to say in Item 4, "Purpose of Transaction", what it intends to do. A holder with no such intent, such as many index and passive funds, may file the shorter Schedule 13G. Both are amended when the stake changes, including when it falls below 5%.
Every row here is one of those filings, linked to the filing itself. Percentages and share counts are exactly as the holder filed them, for the holder the filing names; an amendment showing a lower figure is shown as filed. Item 4 text is quoted word for word. Where a 13D's Item 4 contains a sentence stating a definite intent to influence the company, that sentence is marked and quoted; the page does not describe the holder or its motives beyond the words it filed. Nothing here is investment advice.