# EDGAR Filing Document

**Accession Number:** 0002088256
**File Stem:** 0000950142-26-001035
**Filing Date:** 2026-4
**Character Count:** 11305
**Document Hash:** ca8d374d99988b45935d84e9896833d2
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000950142-26-001035.hdr.sgml**: 20260401

**ACCESSION NUMBER**: 0000950142-26-001035

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20260401

**DATE AS OF CHANGE**: 20260401

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Horizon Quantum Holdings Ltd.
- **CENTRAL INDEX KEY:** 0002088256
- **STANDARD INDUSTRIAL CLASSIFICATION:** SERVICES-COMPUTER PROGRAMMING SERVICES [7371]
- **ORGANIZATION NAME:** 06 Technology
- **EIN:** 000000000
- **STATE OF INCORPORATION:** U0
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-95574
- **FILM NUMBER:** 26830373

**BUSINESS ADDRESS:**
- **ADDRESS IS A NON US LOCATION:** YES
- **STREET 1:** ALICE@MEDIAOPOLIS
- **STREET 2:** 29 MEDIA CIRCLE #05-22
- **CITY:** SINGAPORE
- **PROVINCE COUNTRY:** U0
- **ZIP:** 138565
- **BUSINESS PHONE:** 6581015024

**MAIL ADDRESS:**
- **ADDRESS IS A NON US LOCATION:** YES
- **STREET 1:** ALICE@MEDIAOPOLIS
- **STREET 2:** 29 MEDIA CIRCLE #05-22
- **CITY:** SINGAPORE
- **PROVINCE COUNTRY:** U0
- **ZIP:** 138565

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Horizon Quantum Holdings Pte. Ltd.
- **DATE OF NAME CHANGE:** 20251230

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Rose Holdco Pte. Ltd.
- **DATE OF NAME CHANGE:** 20250924
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** IonQ, Inc.
- **CENTRAL INDEX KEY:** 0001824920
- **STANDARD INDUSTRIAL CLASSIFICATION:** SERVICES-COMPUTER INTEGRATED SYSTEMS DESIGN [7373]
- **ORGANIZATION NAME:** 06 Technology
- **EIN:** 852992192
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D

**BUSINESS ADDRESS:**
- **STREET 1:** 4505 CAMPUS DRIVE
- **CITY:** COLLEGE PARK
- **STATE:** MD
- **ZIP:** 20740
- **BUSINESS PHONE:** (301) 298-7997

**MAIL ADDRESS:**
- **STREET 1:** 4505 CAMPUS DRIVE
- **CITY:** COLLEGE PARK
- **STATE:** MD
- **ZIP:** 20740

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** dMY Technology Group, Inc. III
- **DATE OF NAME CHANGE:** 20200915

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**Horizon Quantum Holdings Ltd.**

*(Name of Issuer)*

**Class A Ordinary Shares**

*(Title of Class of Securities)*

**—**

*(CUSIP Number)*

**Paul T. Dacier**<br>4505 Campus Drive<br>College Park MD 20740<br>(301) 298-7997

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**03/19/2026**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**IonQ, Inc.** | Name of reporting person<br>**IonQ, Inc.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**4230118.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**4230118.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**4230118.00** | Aggregate amount beneficially owned by each reporting person<br>**4230118.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**13.3%** | Percent of class represented by amount in Row (11)<br>**13.3%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**CO** | Type of Reporting Person (See Instructions)<br>**CO** | |

---

**Comment for Reporting Person:** Note to Row 13: Based on 31,833,549 Class A Ordinary Shares issued and outstanding as of March 20, 2026 according to the Form 20-F filed by Horizon Quantum Holdings Ltd. (the "Issuer") on March 25, 2026.

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Class A Ordinary Shares

**(b) Name of Issuer:**
Horizon Quantum Holdings Ltd.

**(c) Address of Issuer's Principal Executive Offices:**
29 MEDIA CIRCLE #05-22, Singapore, U0, 138565

**Item 4. Purpose of Transaction**

The information set forth in Item 3 and Item 6 is incorporated by reference in its entirety into this Item 4.

The Reporting Person acquired the reported securities for investment purposes.  Subject to the terms of, including the rights and obligations contained in, the Subscription Agreement and the Side Letter, as further described in Item 6, the Reporting Person intends to review its investment in the Issuer on a continuing basis.  Depending on various factors, including, without limitation, the Issuer's financial position and strategic direction, actions taken by the Board of Directors of the Issuer (the "Issuer Board"), current and anticipated future price levels of the Issuer's securities, the relative attractiveness of alternative business and investment opportunities and other general economic and market conditions, the Reporting Person may in the future take such actions with respect to its investment as it considers appropriate, which may include, without limitation:

- communicating with the Issuer's management and the Issuer Board, including any member thereof and other securityholders of the Issuer and other relevant parties;
- exercising the Reporting Person's right under the Side Letter to designate a member of the Issuer Board;
- acquiring additional securities of the Issuer (which may include rights or securities exercisable or convertible into securities of the Issuer) or disposing of some or all such securities then owned by the Reporting Person from time to time, in each case, in the open market or in privately negotiated transactions;
- proposing, considering or participating in a merger, reorganization, take-private transaction that could result in the de-listing or de-registration of the Class A Ordinary Shares or other extraordinary corporate transaction, including pursuant to the Reporting Person's right of first notification provided for in the Side Letter;
- security offerings and/or stock repurchases by the Issuer;
- sales or acquisitions of assets or businesses;
- changes to the capitalization or dividend policy of the Issuer;
- other material changes to the Issuer's business or corporate structure, including changes in management or the composition of the Issuer Board; or
- monitoring the commercial arrangement between the Issuer and the Reporting Person.

To facilitate its consideration of such matters, the Reporting Person may retain consultants and advisors and may enter into discussions with potential sources of capital and other third parties. The Reporting Person will likely take some or all of the foregoing steps at preliminary stages in its consideration of various possible courses of action before forming any intention to pursue any particular plan or direction.

Except as described in this Schedule 13D, the Reporting Person does not have any present plans or proposals that relate to or would result in any of the actions described in Item 4 of Schedule 13D, although the Reporting Person, at any time and from time to time, may review, reconsider and change such position and/or change its purpose and/or develop such plans and may seek to influence management of the Issuer or the Issuer Board with respect to the business and affairs of the Issuer and may from time to time consider pursuing or proposing such matters with advisors, the Issuer or other persons.

**Item 5. Interest in Securities of the Issuer**

**(a)**
The information set forth in the facing pages of this Schedule 13D with respect to the beneficial ownership of the Reporting Person is incorporated by reference into this Item 5.

**(b)**
The number of shares as to which there is sole power to vote or to direct the vote, shared power to vote or to direct the vote, sole power to dispose or to direct the disposition, or shared power to dispose or to direct the disposition are set forth on rows 7 through 11 and row 13 of the cover pages of this Schedule 13D and are incorporated herein by reference.

**(c)**
Except for the transactions described in Item 4 of this Schedule 13D, the Reporting Person has not engaged in any transaction during the past 60 days involving the Class A Ordinary Shares of the Issuer.

**Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.**

Subscription Agreement

In connection with the De-SPAC Transaction, the Reporting Person entered into the Subscription Agreement pursuant to which, among other things, the Reporting Person is entitled to certain rights, including the right to demand that that the Issuer file a registration statement or request that its shares be covered by a registration statement. The terms and provisions of the Subscription Agreement are described more fully in the Issuer's Form 20-F dated March 19, 2026 (the "Form 20-F"), and the above summary is qualified by reference to such description and the full text of the Subscription Agreement and the amendment thereto, which are filed as Exhibits 1 and 2 to this Schedule 13D and are incorporated herein by reference.

Side Letter

In connection with the De-SPAC Transaction and the execution of the Subscription Agreement, the Reporting Person entered into the Side Letter, which, among other things, provides the Reporting Person with the right to designate a member of the Issuer Board and a right of first notification over certain transactions, in each case subject to the Reporting Person maintaining certain ownership thresholds in the Issuer. The terms and provisions of the Side Letter are described more fully in the Form 20-F and the above summary is qualified by reference to such description and the full text of the Side Letter and the amendment thereto, which are filed as Exhibits 3 and 4 to this Schedule 13D and are incorporated herein by reference.

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** IonQ, Inc.

**Signature:** /s/ Paul T. Dacier

**Name/Title:** Paul T. Dacier, Chief Legal Officer and Corporate Secretary

**Date:** 04/01/2026