The S-4 effectiveness removes the last regulatory hurdle for the reverse merger. Expect the merger to close imminently, after which the combined entity will trade under a new name/ticker. Monitor for the closing 8-K and post-merger capital structure details.
Price Chart
Executive Summary
The SEC declared effective Pulmatrix's S-4 registration statement (File No. 333-297342) on September 25, 2026, clearing the way for the pending reverse merger with Eos SENOLYTIX. This procedural milestone allows the merger to proceed, after which current Pulmatrix stockholders will own only ~6% of the combined entity. The company receives no new capital from this effectiveness.
Key Facts
- Effectiveness date: September 25, 2026
- S-4 registration for reverse merger with Eos SENOLYTIX declared effective
- Current Pulmatrix stockholders to own ~6% of combined company post-merger
- Company receives no proceeds from this registration
- Pre-revenue biotech with only $3.3M cash as of March 31, 2026
Financial Impact
Massive dilution: current shareholders diluted to ~6% ownership; no new capital raised
Risk Factors
- Extreme dilution for current PULM shareholders (~94% ownership loss)
- Pre-revenue combined entity with uncertain pipeline prospects
- Potential for further dilutive financing post-merger given low cash balance
Investment Themes
Documents Analyzed
This report is based on 3 SEC documents filed with EDGAR.
| Document | Accession Number |
|---|---|
| EFFECT Filing (Primary) | 9999999995-26-003062 |
| Document: 9999999995-26-003062-index.html | 9999999995-26-003062 |
| Document: 9999999995-26-003062.txt | 9999999995-26-003062 |
Filters
| Type | Now | ||||
|---|---|---|---|---|---|
Oct 23, 2026 3d ago | EFFECT | $1.48 | awaiting T+5 | — | $1.48 (−0.00%) |
Oct 22, 2026 4d ago | 425 | $1.42 | awaiting T+5 | — | $1.48 (+4.23%) |
Oct 13, 2026 13d 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 23d ago | S-3/A | $1.48 $1.43 | ▲ +3.38% | ▲ +3.80% | $1.48 (−0.00%) |
Sep 28, 2026 28d 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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