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5%+ stakes · Schedule 13D and 13G

Arqit Quantum Inc.: 5%+ holders

Who has reported owning 5% or more of Arqit Quantum Inc., from Schedule 13D and 13G filings: each holder's stake as filed, the timeline, and the purpose each 13D states, quoted.

At 5% or more2
Filings7
Latest filing2026-09-10

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

HolderPercentSharesLatestEvent date
Heritage Assets SCSp38.6%9,249,964SCHEDULE 13D/A, 2026-05-262026-05-21
Notion Capital III LP10%1,812,206SCHEDULE 13G/A, 2026-09-102026-06-26
Millennium Management LLC0.3%58,621SCHEDULE 13G, 2026-06-232026-06-16

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

FiledHolderPercentFiling
2025-08-26Heritage Assets SCSp49.6%SCHEDULE 13D/A
2025-09-24Heritage Assets SCSp46%SCHEDULE 13D/A
2025-10-20Heritage Assets SCSp43.2%SCHEDULE 13D/A
2025-11-12Heritage Assets SCSp41.8%SCHEDULE 13D/A
2026-05-26Heritage Assets SCSp38.6%SCHEDULE 13D/A
2026-06-23Millennium Management LLC0.3%SCHEDULE 13G
2026-09-10Notion Capital III LP10%SCHEDULE 13G/A

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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.

Cite this page

Permanent URL: https://mentionfox.com/stakes/arqit-quantum
Last updated 2026-09-27
Primary record: SEC filing 1 · SEC filing 2 · SEC filing 3 · SEC filing 4
Arqit Quantum Inc. 5%+ holders: 2 at 5% or more, largest Heritage Assets SCSp 38.6%. MentionFox, 2026-09-27. https://mentionfox.com/stakes/arqit-quantum