Private company
Who owns Siam Polyethylene Company Limited
One company in the researched set discloses a stake in Siam Polyethylene Company Limited, none of it sized by anyone who discloses it. Siam Polyethylene Company Limited is private, so no 13F reports it: a 13F covers exchange listed positions only. These figures exist because each holder disclosed the stake in its own filings.
Siam Polyethylene Company Limited - Profile
- Type
- joint venture
- Based in
- Thailand
Siam Polyethylene Company Limited is a Thai petrochemical producer and the polyethylene business of the SCGC-Dow Group, the manufacturing partnership between Dow and Thailand's SCG Chemicals that dates back to 1987. It makes polyethylene resin in Thailand alongside three sister companies in the same group, Siam Polystyrene, Siam Styrene Monomer and Siam Synthetic Latex, which between them produce polystyrene, styrene monomer, latex and specialty elastomers. Siam Polyethylene also holds a 12.5 percent interest in Map Ta Phut Olefins Company, the Thailand based cracker venture that manufactures propylene and ethylene. SCG Chemicals lists the company among the joint venture businesses it operates with Dow.
Source
Siam Polyethylene Company Limited files nothing with the SEC, so none of this comes from a filer record. The description was written for this site in August 2026 from Dow Inc. Form 10-K for the year ended 31 December 2025 (SEC), Dow Inc. Form 10-K Exhibit 21, subsidiaries as of 31 December 2025 (SEC), SCG Chemicals company structure and Dow Thailand Group, About Us. The ownership figures below come from the holders' filings instead, and are sourced row by row.
The disclosed stakes
One row per position. Where a holder reports the same company in two share classes, both rows are shown rather than summed, because the class is part of a position's identity.
Where each figure comes from
A private stake has no ownership form behind it, so the source is always the holder's own filing or disclosure. Anything modelled says so, with the arithmetic.
- Dow Inc.. Thai equity-method joint venture (SCGC-Dow Group) manufacturing polyethylene. Percentage taken directly from the 10-K table, which states 50.00 percent; written here as 50.0, not 0.5. This entity also carries Dow's 12.50 percentage-point indirect interest in Map Ta Phut, see that row. No individual carrying value is disclosed for Siam Polyethylene itself: covered by the same combined balance described on the EQUATE row, so value_usd stays null. source
What this page is not
It is not a complete register. It lists the holders who happen to be inside the researched set and disclosed the stake themselves. A private company can have many other shareholders, and nothing here rules them out: venture investors, founders and employees usually appear in no public filing at all. Percentages are of Siam Polyethylene Company Limited where a holder stated one, and are missing where no holder did.