The coordinated Form 144 filings by MPM funds signal a clear intent to reduce their position in HOWL. Given the tiny market cap ($25M) and the prior 30-day insider selling of $733K, this creates substantial overhang. Traders should expect continued selling pressure and consider short positions or avoiding long exposure until the selling is absorbed. Monitor for actual sales on Form 4 filings.
Price Chart
Executive Summary
Three MPM-affiliated funds (MPM BioVentures 2014, L.P., MPM BioVentures 2014 (B), L.P., and MPM Oncology Innovations Fund LP) filed Forms 144 on May 18, 2026, signaling intent to sell a combined 290,419 shares of Werewolf Therapeutics (HOWL) worth approximately $149,595 at the filing date. This represents a significant insider selling event from the company's largest venture backer, with the shares originating from a private placement in May 2021. The filing comes amid a $25M market cap and recent heavy insider selling ($733K in prior 30 days), amplifying the bearish signal.
Key Facts
- Three MPM funds filed Form 144 to sell 290,419 shares of HOWL common stock.
- Estimated aggregate value of proposed sale: $149,594.83.
- Shares were acquired in a private placement on May 4, 2021.
- MPM is a major venture capital investor and likely the largest shareholder in HOWL.
- Recent insider activity (30d) shows 10 sells totaling $733K prior to this filing.
- HOWL has a market cap of only $25M, making this a material percentage of float.
- The filing date is May 18, 2026; the proposed sale is planned for the open market.
Financial Impact
Proposed sale of 290,419 shares valued at ~$149,595, representing a significant portion of the $25M market cap.
Risk Factors
- Form 144 is an intent to sell; the sale may not be executed or may be at a different price.
- MPM may be selling for portfolio management reasons unrelated to company fundamentals.
- The stock could rally on positive pipeline news, overriding selling pressure.
Market Snapshot
Investment Themes
Documents Analyzed
This report is based on 5 SEC documents filed with EDGAR.
| Document | Accession Number |
|---|---|
| 144 Filing (HOWL) — Batch item 1 | 0001628280-26-036038 |
| Document: 0001628280-26-036038-index.html | 0001628280-26-036037 |
| Document: 0001628280-26-036038.txt | 0001628280-26-036039 |
| 144 Filing (HOWL) — Batch item 4 | 0001628280-26-036037 |
| 144 Filing (HOWL) — Batch item 5 | 0001628280-26-036039 |
Filters
| Type | Now | ||||
|---|---|---|---|---|---|
Oct 26, 2026 today | S-4/A | $0.9806 | awaiting T+5 | — | $1.01 (−3.00%) |
Sep 22, 2026 4w ago | S-4 | $0.9894 $0.9223 | ▲ +6.78% | ▲ +6.11% | $1.01 (−2.08%) |
Sep 21, 2026 5w ago | SC 13G | $0.9800 $0.9300 | ▼ −5.10% | ▼ −4.08% | $1.01 (+3.06%) |
Aug 21, 2026 9w ago | 425 | $0.8740 $0.9433 | ▲ +7.93% | ▲ +7.46% | $1.01 (+15.56%) |
Aug 21, 2026 9w ago | 8-K | $0.8740 $0.9433 | ▲ +7.93% | ▲ +7.46% | $1.01 (+15.56%) |
Aug 21, 2026 9w ago | Press Release | $0.8740 $0.9433 | ▼ −7.93% | ▼ −7.46% | $1.01 (−15.56%) |
Jul 31, 2026 12w ago | 8-K | $0.3531 $0.3971 | ▲ +12.46% | ▲ +8.95% | $1.01 (+186.04%) |
Jul 31, 2026 12w ago | Press Release | $0.3531 $0.3971 | ▲ +12.46% | ▲ +8.95% | $1.01 (+186.04%) |
Jun 29, 2026 17w ago | 144 | $0.3599 $0.3200 | ▲ +11.09% | ▲ +11.69% | $1.01 (−180.63%) |
Jun 29, 2026 17w ago | 144 | $0.3599 $0.3200 | ▲ +11.09% | ▲ +11.69% | $1.01 (−180.63%) |
US Market Status
Subscribe to SecBot
Get Real-Time SEC Filing Intelligence
Comprehensive SEC filing analysis delivered the moment filings hit EDGAR. Sentiment scoring, impact analysis, and actionable insights for every material event.
Create a free account Live analysis, Telegram alerts, watchlists and the MCP server for subscribers