Spread
Plain definition. A spread is the gap between the bid price and the asked price of a security, as the SEC described it in December 2003.
Technical definition. In a December 2003 request for comments on mutual fund transaction costs, the SEC said spread costs arise indirectly when a fund buys a security from a dealer at the “asked” price, slightly above current value, or sells to a dealer at the “bid” price, slightly below it. These costs include both an imputed commission on the trade and any market impact cost tied to the trade. The SEC classed spread as an implicit cost that cannot be calculated directly, though it can be estimated from data collected some time after the trade is executed.
On this site
On this site, Spread comes up in Where does XRP trade, and how much of its reported trading volume is real?, How do buying and selling XRP work, and where can people do it?, What fees do I really pay to buy XRP, and what’s cheapest? and Are crypto ATMs a safe or sensible way to buy XRP?.
Source
SEC.gov | Request for Comments on Measures To Improve Disclosure of Mutual Fund Transaction Costs (sec.gov), read October 1, 2026.