Free float
What is Free float?
Free float is the portion of a company's outstanding shares considered readily available for public investment after excluding specified strategic, controlling, locked, or restricted holdings. It is a methodology-based investability estimate rather than a direct measure of daily liquidity. Provider exclusions, ownership disclosure, rounding bands, multiple listings, and effective dates can produce different float values for the same issuer and materially change index weights. Beneficial ownership data can also lag or remain incomplete.
Beneficial ownership data can lag, remain incomplete, or use reporting thresholds that obscure investable supply.
How float is defined
Index providers and regulators use different exclusion rules for governments, founders, families, parent companies, cross-holdings, insiders, employee plans, and long-term strategic owners. Some apply bands rather than exact percentages. Public float for securities-law purposes may differ from investable weight factor in an index, so provider and methodology must be named.
Example
A company has 100 million shares, of which a founder holds 35 million and a strategic corporate owner holds 15 million. A provider excluding both assigns 50% free float. If it rounds investability to 55%, its index capitalization differs from an exact public-float calculation despite the same underlying ownership register.
Why float matters
Float affects index weights, trading capacity, ownership concentration, price impact, and eligibility. Low-float shares can show large price moves on modest volume and may be vulnerable to squeezes. High total market capitalization does not guarantee investable depth when a controlling holder owns most shares. Float changes after offerings, lockup expiries, buybacks, or strategic transactions.
Limitations
Beneficial ownership data can be delayed, incomplete, or obscured through nominees. A nominally public block may not trade, while an excluded holder can sell. Free float is not the same as daily liquidity, because turnover, borrow, market makers, and investor concentration matter. Depositary receipts and multiple listings require reconciliation to avoid double counting.
Practical checklist
Record total shares, excluded holders, provider, bands, review date, and effective date. Reconcile filings, lockups, placements, buybacks, conversions, and class structures. Use point-in-time float in backtests and realistic capacity in implementation. Pair float with volume, spread, order-book depth, ownership, and securities lending rather than treating one percentage as complete liquidity.
Also known as: public float, float-adjusted shares
Sources and further reading
- Stocks: Frequently Asked Questions, Investor.gov, U.S. Securities and Exchange Commission