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Factorial Energy (FAC) co-founders disclose 19.1% beneficial ownership stake

Filing Impact
(Moderate)
Filing Sentiment
(Neutral)
Form Type
SCHEDULE 13D

Rhea-AI Filing Summary

Factorial Energy Inc.’s co-founders Siyu Huang and Yingchao (Alex) Yu jointly report beneficial ownership of 21,597,865 shares of the company’s common stock equivalents, representing about 19.1% of the total outstanding common stock. Their stake includes Series B common stock with ten votes per share and stock options exercisable within 60 days.

The position arises from a June 5, 2026 business combination in which legacy Factorial Inc. merged into a subsidiary of Cartesian Growth Corporation III, which then became Factorial Energy Inc. The co-founders are subject to staggered lock-up restrictions on most of their shares for up to one year, but hold registration rights that will allow resales after a resale registration statement is declared effective.

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Beneficial ownership 21,597,865 shares Aggregate common stock equivalents beneficially owned by co-founders
Ownership percentage 19.1% Percent of total outstanding common stock represented by co-founders’ holdings
Series A outstanding 91,510,501 shares Series A Common Stock reported outstanding as of June 5, 2026
Series B outstanding 15,512,744 shares Series B Common Stock held in aggregate by the co-founders as of June 5, 2026
Huang stock options 4,090,616 shares Series A Common Stock underlying employee stock options for Dr. Huang, exercisable within 60 days
Yu stock options 1,994,505 shares Series A Common Stock underlying employee stock options for Dr. Yu, exercisable within 60 days
Six-Month Lock-Up Date 180 days after Closing Date First tranche release for 25% of Lock-up Shares
One Year Lock-Up Date 1 year after Closing Date Final tranche release for 50% of Lock-up Shares
Business Combination financial
"On June 5, 2026, pursuant to the Business Combination Agreement..."
A business combination happens when two or more companies join together to operate as one, like two friends merging their teams into a single group. This is important because it can change how companies grow, compete, and make money, often making them bigger and more powerful in the market.
Series B Common Stock financial
"shares of Issuer's Series B Common Stock, par value $0.00001 per share..."
beneficial ownership financial
"This statement of beneficial ownership on relates to the Series A Common Stock..."
Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.
Lock-up Shares financial
"certain Legacy Factorial stockholders... will be prohibited from transferring... the "Lock-up Shares""
A&R Registration Rights Agreement financial
"entered into an amended and restated registration rights agreement ("A&R Registration Rights Agreement")"
Resale Registration Statement financial
"file... a registration statement registering the resale of certain shares... (the "Resale Registration Statement")"
A resale registration statement is a document filed with regulators that allows existing shareholders to sell their shares to the public. It provides the necessary legal approval and information for these shares to be resold on the market, helping to increase the availability of shares for trading. For investors, it signals that shares held by current owners can be offered for sale, potentially affecting share prices and market liquidity.
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30347G103

(CUSIP Number)
Siyu Huang
c/o Factorial Energy Inc., 805 Middlesex Turnpike
Billerica, MA, 01821
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)


If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).




schemaVersion:


SCHEDULE 13D






SCHEDULE 13D






SCHEDULE 13D


Huang Siyu
Signature:/s/ Siyu Huang
Name/Title:Siyu Huang
Date:06/12/2026
Yu Yingchao
Signature:/s/ Yingchao Yu
Name/Title:Yingchao Yu
Date:06/12/2026

FAQ

How much of Factorial Energy (FAC) do the co-founders beneficially own?

The co-founders report beneficial ownership of 21,597,865 common stock equivalents, representing about 19.1% of Factorial Energy’s total outstanding common stock. This includes Series B shares and employee stock options exercisable within 60 days of the statement.

What types of Factorial Energy (FAC) shares do Siyu Huang and Yingchao Yu hold?

Their holdings include Series B Common Stock and Series A Common Stock underlying employee stock options. Series B shares carry ten votes per share and are convertible into Series A on a one-for-one basis, enhancing their voting influence relative to economic ownership.

How did Factorial Energy (FAC) co-founders acquire their reported stake?

They received Factorial Energy securities as merger consideration in a June 5, 2026 business combination between legacy Factorial Inc. and Cartesian Growth Corporation III. Legacy equity and options were converted into new Series A and Series B Common Stock and replacement options.

What lock-up restrictions apply to the Factorial Energy (FAC) co-founders’ shares?

Most of their shares are designated as Lock-up Shares that generally cannot be transferred for 180 days, 270 days, and one year after closing, in 25%, 25%, and 50% tranches. Limited early release is possible if specific trading price conditions are satisfied under the bylaws.

Do Factorial Energy (FAC) co-founders have registration rights for their shares?

Yes. Under an amended and restated registration rights agreement, the company agreed to file a resale registration statement covering certain Series A shares. Co-founders receive piggyback and demand registration rights, facilitating future registered resales of eligible securities.

What is the capital structure of Factorial Energy (FAC) referenced in this filing?

The filing references 91,510,501 shares of Series A Common Stock and 15,512,744 shares of Series B Common Stock outstanding as of June 5, 2026. Each Series B share has ten votes and can convert into one Series A share, concentrating voting power among its holders.