Biggest Small-Cap Gaps 2026-09-08: Float and Dilution, Sourced

Direct answer: On 2026-09-08, PDSB (PDS Biotechnology Corporation) posted the biggest small-cap gap of the session with +193% intraday (opening gap +122%, float 55.97M, volume 351.8M), followed by BNC (CEA Industries Inc.) at +91% intraday (gap +54%, float 41.17M, volume 35.0M). These moves illustrate how a thin float mechanically amplifies the impact of heavy volume, regardless of the underlying catalyst.

The two biggest moves measured on 2026-09-08

The 2026-09-08 session logged two major gaps across US small-caps, measured from float and volume data in the FloatVerify database.

PDSB (PDS Biotechnology Corporation) opened with a +122% gap from the prior close and hit an intraday peak of +193%. The stock traded at $0.304 at the open, with a float of 55.97 million shares and volume of 351,817,163 shares exchanged during the session. The volume/float ratio works out to roughly 6.3x. On a small-cap gapping hard, that kind of turnover means the entire float theoretically churned more than six times in one day.

BNC (CEA Industries Inc.) opened with a +54% gap and peaked at +91% intraday. The opening price was $5.24, the float 41.17 million shares, and volume 34,984,866 shares. The volume/float ratio hit about 0.85x, nearly a full turn of the available float.

These figures are measured facts: the float comes from the latest count available in SEC filings (forms 10-K, 10-Q, SC 13G/D), volume is as reported by market data platforms, and the moves are calculated from official opening, closing, and intraday extreme prices.

Mechanics: why a thin float amplifies moves

The float is the number of shares available for public trading, meaning total shares issued minus blocks held by insiders, founders, institutions subject to lock-up periods, and restricted stock. It's the denominator of the supply/demand equation.

When heavy volume hits a thin float, the supply/demand balance shifts hard. If 100 million shares get bought in a session and the float is only 50 million, that means every available share must change hands twice on average to satisfy demand. Each time a seller exits, a new seller must be found at a higher price to keep absorbing demand. The higher the volume/float ratio, the harder the pressure on price, up or down.

In PDSB's case, the 6.3x ratio means volume representing more than six times the float changed hands. That kind of extreme turnover creates conditions where available sellers become scarce. Buyers must bid up to find counterparties. This is a mechanical process, not a prediction: it describes what happens structurally when volume far exceeds the float.

Dated float and dilution: why this number moves

The float is not a fixed number. It changes with every dilution event or share unlock. ATM (At-The-Market) offerings allow continuous issuance of new shares at market price, directly increasing the float. Warrant or convertible bond conversions create new common shares from derivative instruments. Option exercises (stock options, RSUs) unlock shares reserved for employees or executives. Lock-up expirations release shares held by insiders or early-stage investors after an IPO or PIPE.

Each time one of these happens, the denominator shifts. A stock that had a 40 million share float can jump to 60 million, even 100 million in a few weeks. That instantly changes the mechanical impact of a given volume: 50 million shares of volume represents 1.25x the original float, but only 0.5x the diluted float.

Dating the float matters. An undated float figure is misleading: it may reflect the situation six months ago, before three successive dilutions. FloatVerify dates every float and displays divergences between sources (some platforms update faster than others) instead of showing one falsely certain figure.

Where to read the float: SEC filings and manual calculation

The float never appears directly in an SEC filing. It must be calculated from multiple elements scattered across filings. The 10-K or 10-Q contains the "Outstanding Shares" or "Equity" section giving total shares issued. The SC 13G/D aggregates institutional or insider ownership disclosures (5% and above), meaning blocks unavailable for public trading. The DEF 14A (proxy statement) details executive and director holdings, so restricted blocks. The S-1, S-3, or 424B5 documents recent public or private offerings, so new shares issued. The 8-K signals material events (conversions, mass exercises, unlocks) triggering sudden changes.

The calculation is simple in theory: Float = Total Outstanding Shares − Insider Holdings − Restricted Institutional Holdings − Lock-ups. In practice, this consolidation work is time-consuming and requires cross-referencing multiple sources. Hence the divergences between data platforms. Some only update once per quarter (after the 10-Q), others integrate 8-Ks in real time. FloatVerify displays these divergences rather than hiding them.

SSR, volume, and selling pressure

When a stock drops 10% or more from the prior close, the SSR (Short Sale Restriction) triggers automatically under SEC Regulation SHO. Once active, the SSR bans short sales at the bid: shorts can only enter at the ask or above, limiting their ability to push price down.

The SSR stays active for the rest of the current session and the entire next session. In the context of a big gap, the SSR can play a mechanical role: if the stock gaps sharply up then retraces 10% or more intraday, the SSR triggers and reduces short selling pressure for the rest of the session and the next day. It guarantees no direction, but it does alter the structure of available supply.

For PDSB and BNC, we have no information on SSR activation on 2026-09-08. The information can be verified via SSR lists published by market data platforms, but is not systematically archived in SEC filings.

No established catalyst

The data provided for PDSB and BNC specify no catalyst behind the gaps measured on 2026-09-08. Large moves on small-caps often happen without an immediately identified specific event (FDA announcement, quarterly results, partnership).

Possible catalysts include corporate announcements (press release, 8-K filed during or before the session), rumors or mentions on forums and social media, unusual market maker or fund activity, or short position covering (short squeeze). But none of these are established here. The figures reported (gap, volume, float) are measured facts, not explanations. Attributing an unsourced cause would be speculative. FloatVerify focuses on what is measurable and dated: float, volume, dilution, cash burn — not interpretation of moves.

Recap

Point	Takeaway
Biggest gap	PDSB +193% intraday (gap +122%), float 55.97M, volume 351.8M
Second gap	BNC +91% intraday (gap +54%), float 41.17M, volume 35.0M
Mechanics	Thin float + heavy volume = mechanical amplification of moves
Dated float	The float changes with every dilution; an undated figure is misleading
Where to find it	Calculated from SEC filings (10-K/Q, SC 13G/D, proxy)
SSR	Triggers at -10% vs prior close, limits shorts to the bid
Catalyst	Not established for PDSB and BNC on 2026-09-08; moves measured, causes unsourced

FAQ

What were the biggest small-cap gaps on 2026-09-08?

PDSB (PDS Biotechnology Corporation) posted +193% intraday with a +122% opening gap, followed by BNC (CEA Industries Inc.) at +91% intraday with a +54% gap. These moves occurred on floats of 55.97M and 41.17M shares respectively.

What is the float and where do you find it?

The float is the number of shares available for public trading, excluding shares held by insiders and restricted blocks. You calculate it from SEC filings (10-K, 10-Q, SC 13G/D) posted on EDGAR. It's a dated figure that changes with every dilution or share unlock.

How does a low float amplify price moves?

A low float means few shares are available to absorb demand. When heavy volume hits a thin float, the supply/demand balance shifts hard, amplifying price swings. The higher the volume/float ratio, the more violent the price impact can be.

What is the SSR (Short Sale Restriction)?

The SSR is an SEC rule (Regulation SHO) that triggers automatically when a stock drops 10% or more from the prior close. Once active, it bans short sales at the bid for the rest of the session and the next session, which can reduce selling pressure.

Does the float change often for small-caps?

Yes, small-cap floats shift frequently via dilution (ATM offerings, warrant conversions, option exercises, post-IPO unlocks). Every new share issuance changes the denominator and therefore the mechanical impact of a given volume. That's why FloatVerify dates every figure and displays divergences between sources.

Sources

• SEC EDGAR: sec.gov/edgar — forms 10-K, 10-Q, SC 13G/D, DEF 14A, 8-K.
• Regulation SHO: sec.gov/rules — rules on short sales and SSR.
• Form 10-K: annual report detailing shares issued and capital structure.
• Form 10-Q: quarterly report with updates to outstanding share count.
• Form SC 13G/D: 5%+ ownership disclosures by institutions or insiders.
• FloatVerify database: float sourced and dated, dilution tracked, divergences between sources displayed.

See the float, sourced and dated, on FloatVerify.

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FloatVerify shows the float, dilution and cash burn of US small-caps, every number sourced and dated — and surfaces divergences between sources ("source split") instead of one falsely certain figure.

Disclaimer: FloatVerify is a data tool, not an investment advisory service. Nothing here is a recommendation to buy or sell. Data, not advice.