PTC Therapeutics, Inc. (PTCT) Ownership
PTCT ownership summary
as of October 18, 2026- Institutions
- 122.8% of shares outstanding
- Insiders
- 7.31% of shares outstanding
- Shares outstanding
- 83.5M
- Float
- 73.7M shares available to trade
- Short interest
- 14.89% 9.2M shares short
- Days to cover
- 7.61 short interest down 5.9% vs prior month
- Institutions 122.77%
- Insiders 7.31%
PTCT top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | BlackRock Inc | 16.73% | 14.0M | $827.3M | +1.0M (+7.8%) | June 30, 2026 |
| 2 | RTW INVESTMENTS, LLC | 9.28% | 7.7M | $458.9M | — | June 30, 2026 |
| 3 | Jupiter Topco LLC | 8.67% | 7.2M | $428.7M | +7.2M (0.0%) | June 30, 2026 |
| 4 | HHG PLC | 8.62% | 7.2M | $426.1M | +2.3M (+48.3%) | March 31, 2026 |
| 5 | Vanguard Portfolio Management, LLC | 5.90% | 4.9M | $291.9M | +123,517 (+2.6%) | June 30, 2026 |
| 6 | State Street Corp | 5.51% | 4.6M | $272.4M | +252,433 (+5.8%) | June 30, 2026 |
| 7 | Wellington Management Company LLP | 4.95% | 4.1M | $244.6M | +185,663 (+4.7%) | June 30, 2026 |
| 8 | Vanguard Capital Management, LLC | 4.48% | 3.7M | $221.5M | +62,871 (+1.7%) | June 30, 2026 |
| 9 | Geode Capital Management, LLC | 2.64% | 2.2M | $130.8M | −2,578 (−0.1%) | June 30, 2026 |
| 10 | The Toronto-Dominion Bank | 2.60% | 2.2M | $128.3M | −860,117 (−28.4%) | June 30, 2026 |
| 11 | Westfield Capital Management Company, L.P. | 2.34% | 2.0M | $115.9M | +2.0M (0.0%) | June 30, 2026 |
| 12 | Hood River Capital Management LLC | 2.08% | 1.7M | $103.0M | +74,054 (+4.4%) | June 30, 2026 |
| 13 | William Blair Investment Management, LLC | 2.06% | 1.7M | $102.1M | +1.7M (0.0%) | June 30, 2026 |
| 14 | D. E. Shaw & Co LP | 1.86% | 1.5M | $91.8M | −91,462 (−5.6%) | June 30, 2026 |
| 15 | TANG CAPITAL MANAGEMENT LLC | 1.80% | 1.5M | $88.9M | — | June 30, 2026 |
| 16 | Bank of America Corp | 1.74% | 1.5M | $86.0M | −434,564 (−23.0%) | June 30, 2026 |
| 17 | Driehaus Capital Management LLC | 1.73% | 1.4M | $85.3M | +424,335 (+41.8%) | June 30, 2026 |
| 18 | FMR Inc | 1.68% | 1.4M | $82.8M | −130,101 (−8.5%) | June 30, 2026 |
| 19 | Jefferies Financial Group Inc | 1.63% | 1.4M | $80.4M | +2,583 (+0.2%) | June 30, 2026 |
| 20 | Fuller & Thaler Asset Management Inc | 1.39% | 1.2M | $68.5M | +1.2M (0.0%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 13 holders added 16.6M shares and 5 cut 1.5M.
PTCT top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | iShares Core S&P Small-Cap ETF | 5.96% | 5.0M | $294.5M | +1,074 (+0.0%) | September 30, 2026 |
| 2 | Vanguard MStar Total Stk Mkt Idx Invest | 3.17% | 2.6M | $156.5M | −3,195 (−0.1%) | August 31, 2026 |
| 3 | State Street® SPDR® S&P® Biotech ETF | 2.64% | 2.2M | $130.4M | −41,900 (−1.9%) | September 30, 2026 |
| 4 | iShares Russell 2000 ETF | 2.57% | 2.1M | $126.9M | −24,704 (−1.1%) | September 30, 2026 |
| 5 | Vanguard Health Care Inv | 2.45% | 2.0M | $121.3M | +9,634 (+0.5%) | June 30, 2026 |
| 6 | Vanguard Small Cap Index | 2.14% | 1.8M | $105.8M | −124,116 (−6.5%) | September 30, 2026 |
| 7 | Vanguard MStar Small Cap Growth Indx Inv | 1.19% | 994K | $58.9M | −101,687 (−9.3%) | September 30, 2026 |
| 8 | Janus Henderson Global Life Sciences D | 1.18% | 982K | $58.2M | −13,413 (−1.3%) | August 31, 2026 |
| 9 | Janus Global Life Science AUSD | 1.13% | 944K | $55.9M | +7,924 (+0.8%) | June 30, 2026 |
| 10 | Janus Henderson Glb Life Scn I2 USD | 1.13% | 943K | $55.9M | −708 (−0.1%) | August 31, 2026 |
| 11 | Fidelity Small Cap Index | 1.08% | 905K | $53.6M | +7,575 (+0.8%) | July 31, 2026 |
| 12 | Hood River Small-Cap Growth Instl | 1.00% | 832K | $49.3M | −57,126 (−6.4%) | June 30, 2026 |
| 13 | Janus Henderson Hrzn Biotec E2 USD | 0.98% | 816K | $48.3M | +12,993 (+1.6%) | June 30, 2026 |
| 14 | iShares S&P Small-Cap 600 Growth ETF | 0.93% | 773K | $45.8M | — | September 30, 2026 |
| 15 | State Street SPDR Port S&P 600 Sm CpETF | 0.91% | 761K | $45.1M | — | September 30, 2026 |
| 16 | iShares Russell 2000 Growth ETF | 0.79% | 662K | $39.2M | −838 (−0.1%) | September 30, 2026 |
| 17 | iShares Biotechnology ETF | 0.75% | 622K | $36.8M | −4,712 (−0.8%) | September 30, 2026 |
| 18 | Harbor Small Cap Growth Instl | 0.73% | 613K | $36.3M | +54,800 (+9.8%) | September 30, 2026 |
| 19 | Pictet-Biotech P USD | 0.71% | 589K | $34.9M | −2,388 (−0.4%) | June 30, 2026 |
| 20 | Janus Henderson Triton D | 0.65% | 541K | $32.0M | — | August 31, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
PTCT insider transactions
latest 20| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-04-21 | Matthew B Klein | Sell | $70.91 | 2,850 | $202,094 |
| 2026-04-06 | Mark Elliott Boulding | Sell | $69.45 | 2,265 | $157,304 |
| 2026-04-02 | Lee Scott Golden | Sell | $67.99 | 829 | $56,364 |
| 2026-04-01 | Neil Gregory Almstead | Sell | $69.04 | 52,003 | $3.6M |
| 2026-03-12 | Matthew B Klein | Sell | $64.08 | 2,662 | $170,581 |
| 2026-03-10 | Stephanie Okey | Sell | $70.00 | 15,167 | $1.1M |
| 2026-03-05 | Lee Scott Golden | Sell | $63.38 | 10,000 | $633,800 |
| 2026-03-05 | Neil Gregory Almstead | Sell | $63.38 | 3,989 | $252,823 |
| 2026-03-05 | Stephanie Okey | Sell | $63.38 | 6,333 | $401,386 |
| 2026-02-19 | Mark Elliott Boulding | Sell | $69.48 | 3,019 | $209,760 |
| 2026-02-18 | Christine Marie Utter | Sell | $69.36 | 2,494 | $172,984 |
| 2026-02-18 | Pierre Gravier | Sell | $69.36 | 2,992 | $207,525 |
| 2026-02-18 | Neil Gregory Almstead | Sell | $69.36 | 65 | $4,508 |
| 2026-02-18 | Neil Gregory Almstead | Sell | $69.36 | 3,056 | $211,964 |
| 2026-02-18 | Matthew B Klein | Sell | $69.36 | 7,371 | $511,253 |
| 2026-02-18 | Mark Elliott Boulding | Sell | $69.36 | 3,081 | $213,698 |
| 2026-02-18 | Lee Scott Golden | Sell | $69.36 | 2,484 | $172,290 |
| 2026-02-18 | Eric Pauwels | Sell | $69.36 | 3,019 | $209,398 |
| 2026-02-17 | Mark Elliott Boulding | Sell | $69.29 | 2,813 | $194,913 |
| 2026-01-12 | Eric Pauwels | Sell | $78.70 | 1,024 | $80,589 |
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.
PTCT shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns PTCT
Institutional investors own 122.8% of PTC Therapeutics's shares and insiders 7.31%. The largest holder is BlackRock Inc with 16.73% of the shares (14.0M), as of June 30, 2026. Among the top 20 institutions, 13 added shares and 5 reduced their stake in the latest filings. Short interest is 14.89% of the float, or 7.61 days of average trading volume. The share count rose 150.0% since 2014.
Related: PTCT analyst forecast, PTCT key metrics. See the PTCT stock overview for the latest quote and news.
PTCT ownership FAQ
Who owns the most PTC Therapeutics stock?
The largest shareholders of PTC Therapeutics are BlackRock Inc (16.73%), RTW INVESTMENTS, LLC (9.28%), Jupiter Topco LLC (8.67%), HHG PLC (8.62%), Vanguard Portfolio Management, LLC (5.90%).
What percentage of PTC Therapeutics is owned by institutions?
Institutions hold 122.8% of PTC Therapeutics's shares outstanding; insiders hold 7.31%.
Which funds own PTC Therapeutics?
The largest fund holders of PTC Therapeutics are iShares Core S&P Small-Cap ETF (5.96%), Vanguard MStar Total Stk Mkt Idx Invest (3.17%), State Street® SPDR® S&P® Biotech ETF (2.64%), iShares Russell 2000 ETF (2.57%), Vanguard Health Care Inv (2.45%).
What is PTC Therapeutics's short interest?
9.2M shares of PTC Therapeutics were sold short, 14.89% of the float; at the average daily volume it would take 7.61 days to cover.
Are insiders buying or selling PTC Therapeutics?
Of the latest 20 reported insider transactions in PTC Therapeutics (since January 12, 2026), 0 were purchases and 20 were sales.
How many shares of PTC Therapeutics are outstanding?
PTC Therapeutics has 83.5M shares outstanding, of which 73.7M are in the public float.