noun
discretionary account
A securities account where the broker has authority to make trading decisions on behalf of the client. Technical financial term.
彼は証券会社に売買一任勘定を開設した。
He opened a discretionary account at the securities firm.
A broader term for any account where authority is delegated; 売買一任勘定 specifically refers to trading authority in securities.
Compound of 売買 (trading) + 一任 (entrusting) + 勘定 (account). The exact historical derivation is uncertain; the term is a modern financial expression.