Float (Shares Available for Trading)

Float refers to the number of shares of a public company that are freely available for trading in the open market. Float is calculated by subtracting restricted shares (insider holdings, employee stock options not yet exercisable, shares held by institutional investors under lock-up agreements) from the total shares outstanding.

A company might have 50 million shares outstanding, but if insiders own 30 million shares that cannot be sold under current agreements, the float is only 20 million shares. This 20 million figure — the actual supply available for trading — is what drives price dynamics for short-term traders.

Float Size and Volatility

Float size is inversely correlated with volatility at any given level of trading volume. A stock with a 2 million share float that trades 500,000 shares in a single hour is turning over 25% of its entire available supply — each new order has more price impact. A stock with a 200 million share float trading the same 500,000 shares is turning over 0.25% — individual orders have minimal price impact. This is why low-float stocks (typically under 20 million shares) are the most common vehicles for extreme intraday catalyst moves: catalysts generate buying demand, and when supply is limited, price moves to clear the imbalance.

Float in Catalyst Trading

Float is a key variable in assessing catalyst move potential. A biotech with a 3 million share float and 25% short interest receiving an FDA approval has all the conditions for an extreme move: positive binary catalyst, minimal share supply, and forced short covering adding to the buy-side demand. The same FDA approval on a large-cap biotech with a 500 million share float produces a much smaller percentage move because the supply is sufficient to absorb the demand without dramatic price disruption. TradeAI News incorporates float data into TMS scoring — low float stocks with high-conviction catalysts receive elevated scores that reflect this amplification dynamic.