Use snapshots to prepare a pre-market research list
Start with the largest reported quote changes, then inspect the observation time. A large previous-session move is a research lead, not evidence of fresh pre-market momentum. Check the issuer’s announcements and a broker’s current quotes before comparing sessions.
Keep price, volume and session definitions together
The percentage shown is (ordinary quote price − that quote’s previous close) ÷ previous close × 100. A missing or nonpositive reference produces Unavailable. Quote volume stays with that quote. The aftermarket trade price and size appear separately and never enter the percentage ranking.
The FMP batch aftermarket trade documentation describes trade prices, sizes and timestamps. Those fields alone do not establish that a returned record belongs to this morning, that all trades were captured, or that a quoted size is available to execute now.
Coverage and execution limits
The universe is limited to the provider’s returned S&P 500 and Nasdaq constituent lists. Rankings show at most 20 eligible rows and are not a market-wide screen. Failed or incomplete requests can change the apparent ordering.
Extended-hours liquidity, spreads and execution conditions can differ from regular trading. A historical trade is not a current bid or ask; activity does not guarantee liquidity or a favorable opening price. These are descriptive data, not buy or sell recommendations.
Frequently asked questions
Does this page rank current pre-market movers?
It ranks ordinary quote changes and quote volume within returned index constituents. The separate aftermarket endpoint can contain observations from another session. The tool does not verify a current pre-market session or calculate a pre-market return from a confirmed prior-session close.
Why are aftermarket trades separate?
A trade price, its timestamp and its size describe one reported observation. Mixing that price with an ordinary quote’s previous close or volume can produce a misleading session comparison. Check each timestamp and the reference session before using the data.
Does a missing row mean no trading occurred?
No. Coverage, unavailable fields, failed requests and provider access can omit records. Missing data remain unknown. Refresh retries requests but does not guarantee a new market observation.
Can I execute trades here?
No. This page displays data for research. It does not send orders, establish liquidity or predict the opening price. The linked Finance Agent is a separate research workflow.