The effectiveness of this shelf registration enables the selling stockholder to begin reselling shares immediately, creating near-term selling pressure on an already thinly traded micro-cap. Monitor for any Form 4 filings indicating actual sales by RCM Eos PIPE HOLDINGS, LLC, which would confirm the overhang materializing. The pending reverse merger with Eos SENOLYTIX remains the primary catalyst; the registration is a procedural step that does not change the merger timeline.
Price Chart
Executive Summary
The SEC declared effective Pulmatrix's S-3 shelf registration (File No. 333-296478) on October 22, 2026, enabling the resale of up to 491,607 shares of common stock by the selling stockholder RCM Eos PIPE HOLDINGS, LLC. These shares are issuable upon conversion of Series B Convertible Preferred Stock and as dividend shares, tied to a March 2026 private placement and the pending reverse merger with Eos SENOLYTIX. The company receives no new capital from this registration, and the effectiveness adds potential dilution overhang to an already distressed micro-cap with a $6M market cap.
Key Facts
- S-3 shelf registration (333-296478) declared effective on October 22, 2026.
- Registration covers resale of up to 491,607 shares of common stock by selling stockholder RCM Eos PIPE HOLDINGS, LLC.
- Shares are issuable upon conversion of 1,000 Series B Convertible Preferred Shares (conversion price $2.20/share) and as 8% annual dividend shares.
- The preferred shares were issued in a March 26, 2026 private placement; the company receives no proceeds from this registration.
- Pulmatrix has a market cap of approximately $6M and is pre-revenue, with no approved products.
- The registration is a procedural step tied to the pending reverse merger with Eos SENOLYTIX, where pre-merger Eos stockholders will own ~94% of the combined entity.
Financial Impact
Potential dilution of up to 491,607 shares (approximately 8-10% of current shares outstanding based on $6M market cap and $2.20 conversion price) overhanging the stock; no new capital raised.
Risk Factors
- Immediate resale of registered shares by the selling stockholder could depress the stock price.
- The company is pre-revenue with only $3.3M cash (as of March 31, 2026) and faces going-concern risk if the merger fails to close.
- Post-merger, current Pulmatrix stockholders will own only ~6% of the combined company, resulting in massive dilution.
Market Snapshot
Investment Themes
Documents Analyzed
This report is based on 3 SEC documents filed with EDGAR.
| Document | Accession Number |
|---|---|
| EFFECT Filing (Primary) | 9999999995-26-003316 |
| Document: 9999999995-26-003316-index.html | 9999999995-26-003316 |
| Document: 9999999995-26-003316.txt | 9999999995-26-003316 |
Filters
| Type | Now | ||||
|---|---|---|---|---|---|
Oct 23, 2026 4d ago | EFFECT | $1.48 | awaiting T+5 | — | $1.48 (−0.00%) |
Oct 22, 2026 5d ago | 425 | $1.42 | awaiting T+5 | — | $1.48 (+4.23%) |
Oct 13, 2026 14d ago | 425 | $1.38 $1.43 | ▲ +3.62% | ▲ +4.77% | $1.48 (+7.25%) |
Oct 7, 2026 19d ago | DEFA14A | $1.53 $1.41 | ▼ −7.67% | ▼ −7.39% | $1.48 (−3.08%) |
Oct 2, 2026 24d ago | S-3/A | $1.48 $1.43 | ▲ +3.38% | ▲ +3.80% | $1.48 (−0.00%) |
Sep 28, 2026 29d ago | EFFECT | $1.59 $1.48 | ▲ +6.92% | ▲ +8.12% | $1.48 (+6.92%) |
Sep 25, 2026 4w ago | DEFM14A | $1.59 $1.48 | ▲ +6.92% | ▲ +8.12% | $1.48 (+6.92%) |
Sep 23, 2026 4w ago | S-4/A | $1.67 $1.54 | ▼ −7.78% | ▼ −7.37% | $1.48 (−11.38%) |
Sep 22, 2026 4w ago | 425 | $1.69 $1.52 | ▼ −9.79% | ▼ −9.12% | $1.48 (−12.17%) |
Sep 17, 2026 5w ago | S-4/A | $1.44 $1.61 | ▲ +11.81% | ▲ +10.54% | $1.48 (+2.78%) |
US Market Status
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