Glossary
Wash trade
A wash trade is a trade in which the buyer and seller are the same person, or act together, so that no real change in ownership or risk takes place. In exchange markets it creates false volume or prices. In a broker's own book it is mostly used to transfer profit and loss between linked accounts.
Why it matters for brokers and payment firms
On MT5 books, opposite trades of the same size between accounts that share a passport, device or funding source can move money from one account to another and earn IB rebates. Detection needs trade data joined to KYC and funding.