™A participant quoting a $49.90 bid and $50.10 ask supplies trading interest, but quoted size and availability can change.
Orders & Market Structure
Market maker
A firm that regularly quotes prices at which it is willing to buy and sell.
Plain-English context
Put the definition to work.
A quoting firm is not obliged to supply unlimited size or hold the same spread through every market condition.
Further reading and verification. Examples are hypothetical, not current quotes or recommendations. Product terms, tax treatment and market rules can change. FINRA — order types and execution