Biggest Small-Cap Gaps on 2026-09-01: Float and Dilution Sourced

Direct answer: On September 1, 2026, six US small-caps recorded opening gaps above 40%. GoPro (GPRO) dominated the session with an intraday peak of +122% and an opening gap of +54%, on a float of 184.5 million shares and record volume of 354 million shares. bioAffinity Technologies (BIAF) followed with +83% intraday (gap +69%, float 8.1M), while Olenex (OLOX) posted +46% on a float of 1.41M. These moves illustrate the classic small-cap mechanism: when volume traded approaches or exceeds the float, volatility explodes.

The September 1, 2026 leaderboard

September 1, 2026 produced a series of violent moves concentrated in low-cap stocks. Here's the ranking by maximum intraday amplitude, with the structural data that contextualizes each move.

Ticker	Intraday peak	Opening gap	Float (M)	Price ($)	Volume (M)
GPRO	+122%	+54%	184.50	1.235	354.28
BIAF	+83%	+69%	8.10	6.60	26.73
OLOX	+46%	+40%	1.41	1.10	22.42
DAIC	+37%	+78%	1.21	3.60	11.03
YYGH	+29%	+48%	3.20	1.47	1.19
FCUV	+21%	+58%	0.70	11.56	0.35

This table reveals several counter-intuitive dynamics. Opening gap amplitude doesn't predict intraday amplitude: DAIC gaps +78% but peaks at +37%, while GPRO gaps +54% and climbs to +122%. Volume-to-float ratios vary wildly—GPRO trades 1.92 times its float, BIAF 3.3 times, OLOX 15.9 times. And float size alone doesn't determine amplitude: GPRO (float 184.5M) posts the day's most violent move despite a float 263 times larger than FCUV's.

The gap mechanism: imbalance and delayed opening

An opening gap occurs when the day's first traded price differs significantly from the prior day's last price. This signals an imbalance between buyers and sellers accumulated during market closure. Orders pile up on one side of the book with no immediate counterparty. The market maker or opening system then adjusts the price to find an equilibrium point.

On small-caps, this mechanism amplifies for three structural reasons. Liquidity is fragmented: fewer market makers, fewer institutional participants, less order book depth. Available float is limited—moderate demand in absolute volume can represent a significant fraction of total tradable shares. And media visibility is asymmetric: news released after the close reaches only a fraction of holders, creating pockets of sellers or buyers disconnected from the rest of the market.

On a gapping small-cap, the first minute of trading often resembles a mini-event: market orders placed the prior day execute at prices no one anticipated, stops trigger in cascades, and traders watching volume scanners pile into the ticker the moment it appears. None of the six stocks above had their specific catalyst documented in the data provided here. The absence of an established cause doesn't diminish the reality of the move: the gap is a measurable fact, whether it results from an SEC filing, a press release, social media rumors, or pure technical dynamics.

Float and dilution: why the number changes

Float—the number of shares available for public trading—is often treated as a constant. It changes with every dilutive event. When a company raises funds by issuing new shares (PIPE placement, ATM program, warrant conversion, option exercise), the float increases immediately. Conversely, a stock buyback reduces the float, though this scenario is rare among cash-burning growth small-caps.

The float calculation follows simple logic: total shares issued − reserved shares (held by founders, executives under lock-up, institutional investors under resale restrictions). SEC filings provide the elements of this calculation, but at different dates. The 10-K or 10-Q (quarterly and annual reports) shows shares issued as of an accounting close date. Form 4 reports insider transactions on a rolling basis. Prospectuses (S-1, S-3) detail new issuances and dilution terms.

No database publishes "the" official float in real time. Each vendor reconstructs the figure by cross-referencing these sources, hence the frequent divergences. FloatVerify displays these gaps instead of hiding them: when two sources give 8.10M and 8.45M for the same stock, both numbers appear, dated and sourced. This "source split" approach reflects reality: float is a dated estimate, not an absolute truth.

Intraday volume and float turnover

The ratio of volume traded to float measures how many times the complete stock of available shares theoretically changed hands during the day. This ratio offers a proxy for the intensity of buying or selling pressure.

Take OLOX: float of 1.41M, volume of 22.42M, a ratio of 15.9. Each share of the float was traded an average of nearly 16 times during the day. This level of turnover indicates intense speculation, with rapid round-trips between buyers and sellers. By contrast, YYGH shows a ratio of 0.37 (volume 1.19M against a float of 3.20M): less than a third of the float circulated, suggesting most holders stayed on the sidelines.

GPRO presents an intermediate case: 354.28M volume against 184.50M float, a 1.92 turnover. This figure is high in absolute terms (354 million shares traded) but moderate in relative terms (less than twice the float). The +122% move therefore doesn't stem from hysterical float rotation, but from a sustained directional imbalance: more buyers than sellers, across massive volume.

Volume alone never explains a move. You must cross it with float, bid/ask spread, order book depth, and trading patterns (institutional blocks vs fractional retail). The data above provide only volume and float; fine-grained interpretation would require tick-by-tick order book data, unavailable publicly.

The SSR list and its impact on intraday dynamics

The SSR rule (Short Sale Restriction, Regulation SHO) prohibits short selling at the bid price when a stock drops 10% or more from its prior close. The prohibition applies for the remainder of the triggering session and the following session. Short sellers can then only short at the ask or higher, reducing their ability to brake a bullish move.

Stocks that gap sharply higher then retrace violently can trigger SSR mid-session. Once on the list, short-selling pressure is limited, which can amplify technical bounces. Conversely, a stock already on the SSR list before the open (due to a prior-day drop) enjoys mechanical protection against aggressive shorts from the gap.

The data provided here don't specify whether any of the six stocks were on the SSR list on September 1. This information is public (Nasdaq publishes the daily SSR list) and is part of the standard regulatory context for volatile small-caps. Its absence from this recap doesn't mean it's unimportant, simply that it wasn't measured here.

Where to read the float: primary sources

Float doesn't appear as such in a single SEC form. It's reconstructed from multiple filings:

• 10-K and 10-Q: annual and quarterly reports, "Capital Stock" or "Stockholders' Equity" section, show the number of shares issued and outstanding as of the accounting close date.
• Form 4: insider transaction disclosures (executives, directors, 10%+ holders), allow tracking of insider sales and purchases that shift the float/restricted split.
• Prospectuses (S-1, S-3, 424B): detail new issuances, number of shares offered, attached warrants, conversion terms, and resale restrictions (lock-up).
• 8-K: material event reports, sometimes include closings of private placements (PIPE) that immediately dilute the float.

None of these forms are real-time. The 10-Q has a 45-day lag (40 days for large accelerated filers), Form 4 has a two-business-day delay. Prospectuses are dated as of the transaction closing, but actual share availability may depend on additional conditions (registration, legal opinion). Consequently, the "current" float is always an estimate based on the latest available filing, adjusted for known events since.

FloatVerify automates this reconstruction by scraping SEC filings, cross-referencing dates, and displaying the provenance of each figure. When two sources diverge (for example, one database cites 8.10M and another 8.45M for the same stock on the same date), both values appear with their timestamp and origin. This transparency lets you judge data reliability instead of consuming a single falsely certain figure.

Recap

Point	Takeaway
September 1 gaps	Six small-caps posted gaps ≥ 40%; GPRO peaked at +122% intraday.
Volume vs float	The volume/float ratio measures turnover intensity; OLOX traded 15.9× its float.
Evolving float	Each dilution changes the float; no number is fixed.
SEC sources	10-K, 10-Q, Form 4, S-1/S-3 prospectuses provide calculation elements.
SSR	The Short Sale Restriction rule limits shorts to the ask after a ≥ 10% drop.
Dated data	Any float figure must be accompanied by a date and source to be reliable.

FAQ

What is an opening gap and why do some exceed 50%?

An opening gap is the difference between the prior day's close and the first traded price the next morning. When a major imbalance exists between buyers and sellers before the open—triggered by a catalyst, news, or pre-market volume—the stock opens directly much higher or lower. On small-caps with limited float, the small quantity of available shares amplifies the price gap needed to absorb demand.

What role does float play in the magnitude of an intraday move?

Float (shares available for public trading) determines the quantity of shares the market can exchange. When unusual volume hits a low float, each additional share demanded must be pulled away at a higher price. That's why FCUV (float 0.70M) can jump 21% on 353,196 shares traded, while GPRO (float 184.5M) requires 354 million shares for a comparable move.

Is a small-cap's float fixed or does it change?

Float changes with every dilutive event: new share issuance, warrant conversion, or lifting of restrictions on reserved shares. A company raising funds via a PIPE placement or an ATM (at-the-market) program increases its float overnight. That's why FloatVerify dates every number: the September 1 float isn't the same as August 15 or next week.

What is the SSR (Short Sale Restriction) list and how does a stock get on it?

The SSR rule (Regulation SHO) prohibits short selling at the bid price when a stock drops 10% or more from its prior close. The restriction stays active through the end of the following session. Stocks that gap sharply higher then retrace violently can trigger this protection, temporarily altering supply and demand dynamics.

Where do you find a small-cap's official, dated float?

Float is calculated from SEC filings: the 10-K or 10-Q shows total shares issued, Form 4 tracks insider transactions, and prospectuses (Forms S-1, S-3) detail new issuances. No single number is published directly; you must cross-reference multiple sources and date the measurement. FloatVerify automates this work and displays divergences between sources instead of hiding inconsistencies.

Sources

Float, dilution, and volume data come from publicly accessible primary sources:

• SEC EDGAR: sec.gov/edgar — Forms 10-K, 10-Q, 8-K, S-1, S-3, 424B, Form 4.
• Regulation SHO: sec.gov/investor/pubs/regsho.htm — regulatory framework for the SSR list.
• Nasdaq SSR List: daily list of stocks under Short Sale Restriction, published by Nasdaq.
• Specific SEC forms: 10-K (annual report), 10-Q (quarterly report), 8-K (material event), S-1/S-3 (issuance prospectus), Form 4 (insider transactions).

No recommendation or prediction is made in this recap. The figures above describe what occurred on September 1, 2026, based on measurable, dated data.

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.