After an Activist Files a 13D
An investor who buys more than 5% of a company and wants to influence it must file a 13D within days. Here is what the stock did next, measured from the close of the week the filing came out.
The average 13D
| After | Filings | Median return | Median vs S&P 500 | Average vs S&P 500 | Beat the S&P 500 |
|---|---|---|---|---|---|
| 1 month | 31 | −5.1% | −3.2% | −0.2% | 35% |
| 3 months | 0 | — | — | — | — |
| 6 months | 0 | — | — | — | — |
| 1 year | 0 | — | — | — | — |
Longer periods have fewer filings because our 13D history is still short. The median is the middle result, which one big winner cannot move.
Every new 13D
| Filed | Stock | 1 month | 3 months | 6 months | 1 year |
|---|---|---|---|---|---|
| Oct 2, 2026 | SSTI | — | — | — | — |
| Oct 1, 2026 | INSG | — | — | — | — |
| Oct 1, 2026 | SSM | — | — | — | — |
| Sep 30, 2026 | SSTI | — | — | — | — |
| Sep 30, 2026 | SAMG | — | — | — | — |
| Sep 29, 2026 | BRSP | — | — | — | — |
| Sep 25, 2026 | FMC | — | — | — | — |
| Sep 25, 2026 | RWT | — | — | — | — |
| Sep 24, 2026 | TROO | — | — | — | — |
| Sep 24, 2026 | REAX | — | — | — | — |
| Sep 24, 2026 | TROO | — | — | — | — |
| Sep 22, 2026 | TPVG | — | — | — | — |
| Sep 21, 2026 | PDSB | — | — | — | — |
| Sep 21, 2026 | HSTM | — | — | — | — |
| Sep 21, 2026 | CTNT | — | — | — | — |
| Sep 18, 2026 | NFE | — | — | — | — |
| Sep 18, 2026 | TROO | — | — | — | — |
| Sep 17, 2026 | YI | — | — | — | — |
| Sep 16, 2026 | MTN | — | — | — | — |
| Sep 15, 2026 | SAFX | — | — | — | — |
| Sep 11, 2026 | USAR | — | — | — | — |
| Sep 11, 2026 | AMH | — | — | — | — |
| Sep 10, 2026 | ATER | — | — | — | — |
| Sep 9, 2026 | GPRO | — | — | — | — |
| Sep 9, 2026 | HELP | — | — | — | — |
| Sep 9, 2026 | HELP | — | — | — | — |
| Sep 8, 2026 | SSM | — | — | — | — |
| Sep 8, 2026 | DLPN | — | — | — | — |
| Sep 8, 2026 | PRVA | — | — | — | — |
| Sep 8, 2026 | AGNT | — | — | — | — |
| Sep 4, 2026 | VNRX | −42.5% | — | — | — |
| Sep 4, 2026 | BFNH | — | — | — | — |
| Sep 3, 2026 | NXL | — | — | — | — |
| Sep 3, 2026 | SKYA | — | — | — | — |
| Sep 2, 2026 | DH | — | — | — | — |
| Sep 2, 2026 | DH | — | — | — | — |
| Aug 31, 2026 | FJET | −48.0% | — | — | — |
| Aug 28, 2026 | SHAZ | −2.0% | — | — | — |
| Aug 28, 2026 | VNET | −2.5% | — | — | — |
| Aug 28, 2026 | GOVB | — | — | — | — |
| Aug 28, 2026 | XPON | −21.3% | — | — | — |
| Aug 28, 2026 | BMRA | — | — | — | — |
| Aug 27, 2026 | EZRA | −12.0% | — | — | — |
| Aug 26, 2026 | VOD | +3.1% | — | — | — |
| Aug 26, 2026 | SLE | +29.3% | — | — | — |
| Aug 25, 2026 | MBRX | −6.0% | — | — | — |
| Aug 25, 2026 | HODO | −35.4% | — | — | — |
| Aug 25, 2026 | XPOF | −28.2% | — | — | — |
| Aug 25, 2026 | MBRX | −6.0% | — | — | — |
| Aug 25, 2026 | CHTR | — | — | — | — |
| Aug 24, 2026 | SUZ | +4.0% | — | — | — |
| Aug 24, 2026 | MLM | −8.5% | — | — | — |
| Aug 24, 2026 | CVRX | — | — | — | — |
| Aug 21, 2026 | IMMR | — | — | — | — |
| Aug 21, 2026 | CUE | −1.5% | — | — | — |
| Aug 20, 2026 | SLE | +117.8% | — | — | — |
| Aug 20, 2026 | GPI | −3.2% | — | — | — |
| Aug 20, 2026 | ATXG | — | — | — | — |
| Aug 19, 2026 | PFSA | −59.2% | — | — | — |
| Aug 19, 2026 | BETR | −0.6% | — | — | — |
| Aug 18, 2026 | SUJA | +38.1% | — | — | — |
| Aug 18, 2026 | KPLT | +29.3% | — | — | — |
| Aug 18, 2026 | KPLT | +29.3% | — | — | — |
| Aug 18, 2026 | CNXU | −48.7% | — | — | — |
| Aug 18, 2026 | BRVE | −5.2% | — | — | — |
| Aug 18, 2026 | KPLT | +29.3% | — | — | — |
| Aug 17, 2026 | FEMY | +13.3% | — | — | — |
| Aug 14, 2026 | LCLN | +10.0% | — | — | — |
| Aug 14, 2026 | VATE | — | — | — | — |
| Aug 14, 2026 | QVCG | −13.9% | — | — | — |
| Aug 14, 2026 | MDXH | +54.7% | — | — | — |
| Aug 14, 2026 | APO | −9.0% | — | — | — |
| Aug 14, 2026 | BRVE | −10.5% | — | — | — |
| Aug 13, 2026 | BLSM | — | — | — | — |
Columns show the stock's return minus the S&P 500 (SPY) over the same weeks.
Why 13D filings get watched
A 13D says an investor owns more than 5% and may push for change: a sale of the company, new directors, a buyback, a spin-off. Academic studies of hedge fund activism, such as Brav, Jiang, Partnoy and Thomas (Journal of Finance, 2008), found the stock tends to jump around the filing and that the gain does not usually reverse in the following year.
Much of the jump happens before or on the day of the filing, which is why this page starts counting at the close of the filing week. What is left after that is what a reader could actually have caught.
Only the first 13D by each investor in each stock is counted; amendments are left out. Prices are weekly closes, adjusted for splits. Past results do not predict future ones. Not investment advice. See all new 13D and 13G filings.
About this page
WallStPal explains public SEC filings and congressional stock trade reports in plain English. Nothing is for sale; the site is free and supported by ads.
How to read it
- Form 4
- The form a company insider (officer, director or owner of more than 10%) must file with the SEC within two business days of buying or selling the company's shares.
- 13F
- A quarterly list of U.S. stocks held by an investment manager with more than $100 million, filed within 45 days after each quarter ends.
- STOCK Act
- A 2012 law that requires members of Congress to report stock trades by themselves, a spouse or a dependent child within 45 days.
A real example
In January 2016, when bank stocks were falling, JPMorgan Chase CEO Jamie Dimon bought 500,000 JPMorgan shares with his own money, worth about $26 million. His Form 4 made the purchase public within days, and investors read it as a strong sign of confidence.
Explain it like I'm 13
We read the long, boring forms that grown-ups file with the government and tell you what they say in normal words.
Data from public SEC filings and congressional reports. Information, not investment advice. Check every number against the filing linked on the page.