Trinseo PLC (TSE) Ownership
TSE ownership summary
as of October 18, 2026- Institutions
- 69.2% of shares outstanding
- Insiders
- 5.33% of shares outstanding
- Shares outstanding
- 36.0M
- Float
- 30.8M shares available to trade
- Short interest
- 20.70% 5.7M shares short
- Days to cover
- 8.75 short interest up 37.3% vs prior month
- Institutions 69.22%
- Insiders 5.33%
- Other investors 25.46%
TSE top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | GAMMA Investing LLC | 1.13% | 413K | $478,680 | +410,507 (+19,111.1%) | June 30, 2026 |
| 2 | Kohmann Bosshard Financial Services, LLC | 0.12% | 45K | $51,742 | — | June 30, 2026 |
| 3 | EverSource Wealth Advisors, LLC | 0.01% | 5,375 | $6,235 | −55 (−1.0%) | June 30, 2026 |
| 4 | Mcilrath & Eck, LLC | <0.01% | 1,444 | $1,675 | — | March 31, 2026 |
| 5 | Sunbelt Securities | <0.01% | 64 | $74 | +64 (0.0%) | March 31, 2026 |
| 6 | Essential Partners LLC | <0.01% | 30 | $35 | −36 (−54.5%) | June 30, 2026 |
| 7 | Rothschild Wealth Partners | 0.00% | 7 | $8 | — | June 30, 2026 |
| 8 | Goldman Sachs Asset Management, L.P. | 0.00% | — | — | −580,623 (−100.0%) | March 31, 2026 |
| 9 | Ground Swell Capital, LLC | 0.00% | — | — | −11,765 (−100.0%) | March 31, 2026 |
| 10 | Hanson Mcclain Inc | 0.00% | — | — | −19 (−100.0%) | March 31, 2026 |
| 11 | Acadian Asset Management LLC | 0.00% | — | — | −2,820 (−100.0%) | March 31, 2026 |
| 12 | BlackRock Inc | 0.00% | — | — | −2.4M (−100.0%) | March 31, 2026 |
| 13 | Barclays PLC | 0.00% | — | — | −4,802 (−100.0%) | June 30, 2026 |
| 14 | Amvescap Plc. | 0.00% | — | — | −70,320 (−100.0%) | March 31, 2026 |
| 15 | BNP Paribas Arbitrage, SA | 0.00% | — | — | −8,370 (−100.0%) | March 31, 2026 |
| 16 | AQR Capital Management LLC | 0.00% | — | — | −33,646 (−100.0%) | March 31, 2026 |
| 17 | Amalgamated Financial Corp | 0.00% | — | — | −1,070 (−100.0%) | March 31, 2026 |
| 18 | GSA Capital Partners LLP | 0.00% | — | — | −511,342 (−100.0%) | March 31, 2026 |
| 19 | Advisor Group Holdings, Inc. | 0.00% | — | — | −231 (−100.0%) | March 31, 2026 |
| 20 | CWM, LLC duplicate | 0.00% | — | — | −1,259 (−100.0%) | March 31, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 2 holders added 411K shares and 15 cut 3.6M.
TSE top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | M&G Global Dividend GBP I Acc | 8.12% | 3.0M | $3.4M | — | June 30, 2026 |
| 2 | M&G (Lux) Glb Dividend CI USD Acc | 7.75% | 2.8M | $3.3M | — | June 30, 2026 |
| 3 | Schwab Fundamental U.S. Small CompanyETF | 4.54% | 1.7M | $1.9M | — | September 30, 2026 |
| 4 | ICON Natural Resources and Infras Instl | 1.05% | 384K | $445,208 | −116,200 (−23.2%) | June 30, 2026 |
| 5 | Schwab Fundamental US Small Company Idx | 0.90% | 328K | $381,052 | — | September 30, 2026 |
| 6 | Schwab Small Cap Index | 0.23% | 85K | $98,632 | — | August 31, 2026 |
| 7 | FCH M&G Global Dividend Z USD Cap | 0.19% | 69K | $80,141 | — | March 31, 2026 |
| 8 | iShares Russell 2000 Small-Cap Idx Instl | 0.16% | 59K | $68,421 | — | August 31, 2026 |
| 9 | Nuveen Small Cap Blend Idx R6 | 0.12% | 44K | $51,365 | — | August 31, 2026 |
| 10 | EQ/2000 Managed Volatility IB | 0.10% | 36K | $42,222 | — | August 31, 2026 |
| 11 | Schwab Fundamental U.S. Broad Market ETF | 0.07% | 26K | $30,318 | — | September 30, 2026 |
| 12 | Bridge Builder Small/Mid Cap Value | 0.04% | 16K | $18,278 | — | September 30, 2026 |
| 13 | VALIC Company I Small Cap Index | 0.04% | 14K | $16,058 | — | August 31, 2026 |
| 14 | Vanguard U.S. Eq Idx £ Acc | 0.04% | 14K | $15,827 | — | August 31, 2026 |
| 15 | Pacific Select Small-Cap Index I | 0.02% | 8,856 | $10,273 | — | September 30, 2026 |
| 16 | ATM Small Cap Managed Volatility K | 0.02% | 7,478 | $8,674 | — | August 31, 2026 |
| 17 | 1290 VT Micro Cap K | 0.02% | 6,822 | $7,914 | — | August 31, 2026 |
| 18 | NVIT Small Cap Index Y | 0.02% | 6,312 | $7,322 | — | September 30, 2026 |
| 19 | iShares Russell Small/Mid-Cap Idx K | 0.02% | 5,586 | $6,480 | — | August 31, 2026 |
| 20 | 1290 VT Small Cap Value K | 0.01% | 5,096 | $5,911 | — | August 31, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
TSE insider transactions
latest 3| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2025-08-14 | Matthew Farrell | Buy | $2.43 | 48,609 | $118,120 |
| 2025-08-13 | Matthew Farrell | Buy | $2.45 | 26,391 | $64,658 |
| 2025-08-12 | Matthew Farrell | Buy | $2.29 | 25,000 | $57,250 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
TSE shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns TSE
Institutional investors own 69.2% of Trinseo's shares and insiders 5.33%. The largest holder is GAMMA Investing LLC with 1.13% of the shares (413K), as of June 30, 2026. Among the top 20 institutions, 2 added shares and 15 reduced their stake in the latest filings. Short interest is 20.70% of the float, or 8.75 days of average trading volume. The share count fell 26.6% since 2014.
Related: TSE analyst forecast, TSE key metrics, TSE dividend history. See the TSE stock overview for the latest quote and news.
TSE ownership FAQ
Who owns the most Trinseo stock?
The largest shareholders of Trinseo are GAMMA Investing LLC (1.13%), Kohmann Bosshard Financial Services, LLC (0.12%), EverSource Wealth Advisors, LLC (0.01%), Mcilrath & Eck, LLC (<0.01%), Sunbelt Securities (<0.01%).
What percentage of Trinseo is owned by institutions?
Institutions hold 69.2% of Trinseo's shares outstanding; insiders hold 5.33%.
Which funds own Trinseo?
The largest fund holders of Trinseo are M&G Global Dividend GBP I Acc (8.12%), M&G (Lux) Glb Dividend CI USD Acc (7.75%), Schwab Fundamental U.S. Small CompanyETF (4.54%), ICON Natural Resources and Infras Instl (1.05%), Schwab Fundamental US Small Company Idx (0.90%).
What is Trinseo's short interest?
5.7M shares of Trinseo were sold short, 20.70% of the float; at the average daily volume it would take 8.75 days to cover.
Are insiders buying or selling Trinseo?
Of the latest 3 reported insider transactions in Trinseo (since August 12, 2025), 3 were purchases and 0 were sales.
How many shares of Trinseo are outstanding?
Trinseo has 36.0M shares outstanding, of which 30.8M are in the public float.