Market Maker

Also called: MM, B-book broker, dealing desk

A broker that takes the other side of client trades — provides liquidity in-house rather than routing to external LPs.

Market makers (B-book brokers) profit when clients lose. Reputable market makers run sophisticated risk-management (off-loading large exposures to A-book) and don’t manipulate prices, but the model creates an inherent conflict of interest.

Pros: fixed spreads, instant fills, beginner-friendly. Cons: requotes, conflict of interest, and (rarely) accusations of stop-hunting.