# EDGAR Filing Document

**Accession Number:** 0002135467
**File Stem:** 0001104659-26-073542
**Filing Date:** 2026-6
**Character Count:** 18862
**Document Hash:** 0e8bbb16b5ec981a11348950223fccda
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-26-073542.hdr.sgml**: 20260612

**ACCESSION NUMBER**: 0001104659-26-073542

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20260612

**DATE AS OF CHANGE**: 20260612

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Factorial Energy Inc.
- **CENTRAL INDEX KEY:** 0002049662
- **STANDARD INDUSTRIAL CLASSIFICATION:** MISCELLANEOUS ELECTRICAL MACHINERY, EQUIPMENT & SUPPLIES [3690]
- **ORGANIZATION NAME:** 04 Manufacturing
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-95000
- **FILM NUMBER:** 261087518

**BUSINESS ADDRESS:**
- **STREET 1:** 805 MIDDLESEX TURNPIKE
- **CITY:** BILLERICA
- **STATE:** MA
- **ZIP:** 01821
- **BUSINESS PHONE:** 617-315-9733

**MAIL ADDRESS:**
- **STREET 1:** 805 MIDDLESEX TURNPIKE
- **CITY:** BILLERICA
- **STATE:** MA
- **ZIP:** 01821

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Cartesian Growth Corp III
- **DATE OF NAME CHANGE:** 20241220
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Huang Siyu
- **CENTRAL INDEX KEY:** 0002135467

**ORGANIZATION NAME:**

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

**MAIL ADDRESS:**
- **STREET 1:** C/O FACTORIAL ENERGY INC.
- **STREET 2:** 805 MIDDLESEX TURNPIKE
- **CITY:** BILLERICA
- **STATE:** MA
- **ZIP:** 01821

## Exhibit 99.1

**Exhibit 99.1**

**JOINT FILING AGREEMENT**

The undersigned acknowledge and agree that the foregoing statement on Schedule 13D is filed on behalf of each of the undersigned and that all subsequent amendments to this statement on Schedule 13D may be filed on behalf of each of the undersigned without the necessity of filing additional joint filing agreements. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning him or it contained herein or therein, but shall not be responsible for the completeness and accuracy of the information concerning the others, except to the extent that he or it knows or has reason to believe that such information is inaccurate.

---

| | |
|:---|:---|
| **SIYU HUANG** | **SIYU HUANG** |
| Signature: | /s/ Siyu Huang |
| Name/Title: | Siyu Huang |
| Date: | June 12, 2026 |
| **YINGCHAO YU** | **YINGCHAO YU** |
| Signature: | /s/ Yingchao Yu |
| Name/Title: | Yingchao Yu |
| Date: | June 12, 2026 |

---

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

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**FACTORIAL ENERGY INC.**

*(Name of Issuer)*

**Series A common stock, par value $0.00001 per share**

*(Title of Class of Securities)*

**—**

*(CUSIP Number)*

**Siyu Huang**<br>c/o Factorial Energy Inc.<br>805 Middlesex Turnpike<br>Billerica MA 01821<br>617-315-9733

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

**06/05/2026**

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

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Huang Siyu** | Name of reporting person<br>**Huang Siyu** | |
| 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>**SC** | Source of funds (See Instructions)<br>**SC** | |
| 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>**X1** | Citizenship or place of organization<br>**X1** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**21597865.00** |
| 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>**21597865.00** |
| 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>**21597865.00** | Aggregate amount beneficially owned by each reporting person<br>**21597865.00** | |
| 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>**19.1%** | Percent of class represented by amount in Row (11)<br>**19.1%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Yu Yingchao** | Name of reporting person<br>**Yu Yingchao** | |
| 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>**SC** | Source of funds (See Instructions)<br>**SC** | |
| 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>**X1** | Citizenship or place of organization<br>**X1** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**21597865.00** |
| 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>**21597865.00** |
| 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>**21597865.00** | Aggregate amount beneficially owned by each reporting person<br>**21597865.00** | |
| 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>**19.1%** | Percent of class represented by amount in Row (11)<br>**19.1%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Series A common stock, par value $0.00001 per share

**(b) Name of Issuer:**
FACTORIAL ENERGY INC.

**(c) Address of Issuer's Principal Executive Offices:**
805 MIDDLESEX TURNPIKE, BILLERICA, MA, 01821

This statement of beneficial ownership on Schedule 13D relates to the Series A Common Stock, par value $0.00001 per share (the "Series A Common Stock"), of Factorial Energy Inc., a Delaware corporation (the "Issuer"). The address of the Issuer's principal executive offices is 805 Middlesex Turnpike, Billerica, MA 01821.

**Item 4. Purpose of Transaction**

The information set forth in Items 3 and 6 of this Schedule 13D is hereby incorporated by reference into this Item 4.

The Reporting Persons each intend to review each of their respective investments in the Issuer on a continuing basis. Any actions the Reporting Persons might each undertake may be made at any time and from time to time without prior notice and will be dependent upon each of their respective review of numerous factors, including, but not limited to: an ongoing evaluation of the Issuer's business, financial condition, operations and prospects; price levels of the Issuer's securities; general market, industry and economic conditions; the relative attractiveness of alternative business and investment opportunities; and other future developments. In connection with the vesting, settlement or exercise of equity awards of the Issuer, the Reporting Persons may each have shares of Series A Common Stock withheld for taxes or sold in open-market transactions in connection with the payment of applicable taxes or otherwise.

The Reporting Persons, subject to certain provisions of the law, may each respectively acquire additional securities of the Issuer, or retain or sell all or a portion of the securities then held, in the open market or in privately negotiated transactions. In addition, each of Dr. Huang, including in her positions as Chief Executive Officer and a member of the Board, and Dr. Yu, including in his positions as Chief Technology Officer and a member of the Board, may engage in discussions with other members of management, the Board, and stockholders of the Issuer and other relevant parties or encourage, cause or seek to cause the Issuer or such persons to consider or explore extraordinary corporate transactions, such as: a merger, reorganization or take-private transaction that could result in the de-listing or de-registration of the Series A Common Stock; 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; or other material changes to the Issuer's business or corporate structure, including changes in management or the composition of the Board.

Other than as described above, each of the Reporting Persons do not currently have any plans or proposals that relate to, or would result in, any of the matters listed in Items 4(a)-(j) of Schedule 13D, although, depending on the factors discussed herein, the Reporting Persons may change each of their respective purpose or formulate different plans or proposals with respect thereto at any time.

Dr. Huang, including in her positions as Chief Executive Officer and a member of the Board, and Dr. Yu, including in his positions as Chief Technology Officer and a member of the Board, each participate in deliberations of the Issuer's senior management in the normal course of the Issuer's business that could involve any of the matters set forth in Items 4(a)-(j) of Schedule 13D from time to time, and, in keeping with each of their respective fiduciary duties as an officer and director, may make proposals or recommendations to the Board that could involve such matters from time to time.

In addition, as members of the Issuer's senior management, each of the Reporting Persons participates in Issuer compensatory plans, including plans pursuant to which awards of equity securities are made (including to each of Dr. Huang and Dr. Yu), in the ordinary course of business.

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

**(a)**
The aggregate number and percentage of shares of Series A Common Stock beneficially owned by each Reporting Person and, for each Reporting Person, 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.

Beneficial ownership of shares of Series A Common Stock includes shares of Series A Common Stock which may be acquired upon the conversion of shares of Series B Common Stock. Holders of Series A Common Stock and Series B Common Stock generally vote together as a single class, unless otherwise required by law, the Issuer's certificate of incorporation, or the Issuer's bylaws. Each share of Series A Common Stock is entitled to one vote per share. Each share of Series B Common Stock is entitled to ten votes per share and is convertible at any time at the option of the holder into one share of Series A Common Stock.

As of the date hereof, the Reporting Persons beneficially own 21,597,865 shares of Series A Common Stock in the aggregate, representing beneficial ownership of approximately 19.1% of the total outstanding Common Stock, consisting of: (i) 5,848,182 shares of Series B Common Stock held by Danehy Family Trust, of which Dr. Huang serves as investment trustee, (ii) 1,914,528 shares of Series B Common Stock held by Siyu Huang 2024 Family Trust dated March 1, 2024, of which Dr. Huang serves as investment trustee, (iii) 4,090,616 shares of Series A Common Stock underlying employee stock options held by Dr. Huang vested or to be vested and exercisable within 60 days of this Statement, (iv) 366,840 shares of Series B Common Stock held directly by Dr. Yu, (v) 7,383,194 shares of Series B Common Stock held by North Point Family Trust, of which Dr. Yu serves as investment trustee, and (vi) 1,994,505 shares of Series A Common Stock underlying employee stock options held by Dr. Yu vested or to be vested and exercisable within 60 days of this Statement.

Calculations of the percentage of the total outstanding Common Stock beneficially owned by the Reporting Persons are based on (i) 91,510,501 shares of Series A Common Stock reported to be outstanding as of June 5, 2026, as disclosed in its Current Report on Form 8-K filed with the SEC on June 10, 2026, (ii) 15,512,744 shares of Series B Common Stock held in the aggregate by Dr. Huang and Dr. Yu, which also represents the total number of shares of Series B Common Stock reported to be outstanding as of June 5, 2026, as disclosed in its Current Report on Form 8-K filed with the SEC on June 10, 2026, where each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock and (iii) 6,085,121 shares of Series A Common Stock underlying employee stock options held by the Reporting Persons vested or to be vested and exercisable within 60 days of this Statement.

**(b)**
The information set forth in Item 5(a) of this Schedule 13D is hereby incorporated by reference.

**(c)**
Except for the receipt of Issuer securities in connection with the consummation of the Business Combination as described herein, neither Reporting Person has effected any transaction in the Series A Common Stock during the past 60 days.

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

The information contained in Item 3 of the Schedule 13D is incorporated by reference into this Item 6.

Executive and Director Compensation

Each of Dr. Huang, including in her positions as Chief Executive Officer and a member of the Board, and Dr. Yu, including in his positions as Chief Technology Officer and a member of the Board, has in the past and may in the future receive compensation in the form of Common Stock, restricted stock units, stock options or other securities convertible into Common Stock of the Issuer.

Lock-Up Provisions

The bylaws of the Issuer (the "Bylaws") provide that certain Legacy Factorial stockholders (including the Reporting Persons) will be prohibited from transferring (except for certain permitted transfers) any shares of Common Stock held by such holder (the "Lock-up Shares") beginning on the Closing Date and ending (i) with respect to 25% of the Lock-Up Shares, on the date 180 days after the Closing Date (the "Six-Month Lock-Up Date"), (ii) with respect to 25% of the Lock-Up Shares, on the date 270 days after the Closing Date (the "Nine-Month Lock-Up Date") and (iii) with respect to 50% of the Lock-Up Shares, on the first anniversary of the Closing Date (the "One Year Lock-Up Date" and each of the Six-Month Lock-Up Date, the Nine-Month Lock-Up Date and the One Year Lock-Up Date, a "Lock-Up Termination Date"); provided, however, that, on the dates on which certain trading price conditions are satisfied, such transfer restrictions will terminate with respect to one-third of the Lock-Up Shares ("Early Release Lock-Up Shares"), with such Early Release Lock-Up Shares allocated first among the Lock-Up Shares with the earliest Lock-Up Termination Date that has not yet occurred and successively to each remaining tranche of Lock-Up Shares in chronological order. The foregoing transfer restrictions will not apply to 750 shares of Common Stock held by each such holder and such specified shares are not Lock-up Shares.

Registration Rights Agreement

In connection with the Business Combination, the Issuer and certain stockholders of Legacy Factorial (including the Reporting Persons) entered into an amended and restated registration rights agreement ("A&R Registration Rights Agreement"). Pursuant to the A&R Registration Rights Agreement, among other things, the Issuer agreed that, within 30 calendar days following the Closing Date, the Issuer will file with the SEC (at its sole cost and expense) a registration statement registering the resale of certain shares of the Issuer's Series A Common Stock held by or issuable to the parties thereto (the "Resale Registration Statement"), and the Issuer will use its commercially reasonable efforts to have the Resale Registration Statement declared effective as soon as reasonably practicable after the filing thereof. Such holders will be entitled to customary piggyback registration rights and demand registration rights, including underwritten demands. The Registration Rights Agreement will terminate on the earlier of (a) the seven year anniversary of the date of the Registration Rights Agreement or (b) with respect to any holder party thereto, on the date that such holder no longer holds any Registrable Securities (as defined therein).

The foregoing descriptions of the Bylaws and A&R Registration Rights Agreement do not purport to be complete and are qualified in their entirety by reference to the full text of such agreements, copies of which are included as Exhibits 99.5 and 99.6 to this Statement, respectively.

### 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:** Huang Siyu

**Signature:** /s/ Siyu Huang

**Name/Title:** Siyu Huang

**Date:** 06/12/2026

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:** Yu Yingchao

**Signature:** /s/ Yingchao Yu

**Name/Title:** Yingchao Yu

**Date:** 06/12/2026