6-K - Arqit Quantum Inc.

Form 6-K - Report of foreign issuer [Rules 13a-16 and 15d-16]: SEC Accession No. 0001104659-26-042173

Filing Date: 2026-04-13

Accepted: 2026-04-13 06:00:37

Documents: 3

Period of Report: 2026-04-13

Arqit Quantum Inc. (Filer) CIK : 0001859690 (see all company filings) EIN. : 000000000 | State of Incorp.: E9 | Fiscal Year End: 0930 Type: 6-K | Act: 34 | File No.: 001-40777 | Film No.: 26856331 SIC : 7372 Services-Prepackaged Software (CF Office: 06 Technology)

1 | FORM 6-K | tm2611612d1_6k.htm | 6-K

2 | EXHIBIT 99.1 | tm2611612d1_ex99-1.htm | EX-99.1

3 | GRAPHIC | tm2611612d1_ex99-1img01.jpg | GRAPHIC

SECURITIES AND EXCHANGE COMMISSION

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of April 2026

Commission File Number: 001-40777

(Exact name of registrant as specified in its charter)

2 nd Floor, 3 Orchard Place

London, SW1H 0BF United Kingdom

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

On April 10, 2026, Arqit Quantum Inc. (the “ Company ”) issued a press release entitled “Arqit Quantum Inc. Announces Select Preliminary Financial Results for First Half of Fiscal Year 2026,” in which the Company reported select unaudited preliminary financial results for the six months ended March 31, 2026. A copy of that press release is furnished as Exhibit 99.1 hereto.

The information furnished in this Report of Foreign Private Issuer on Form 6-K, including the information contained in Exhibit 99.1, shall not be deemed to be “filed” for the purposes of Section 18 of the Exchange Act, or otherwise subject to the liabilities of that section, and shall not be deemed to be incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by a specific reference in such filing.

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.