To deal in

To have to do with; to be engaged in; to practice; as, they deal in political matters.
- Locke.
To buy and sell; to furnish, as a retailer or wholesaler; as, they deal in fish.

See also: Deal, Deal

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in periodicals archive ?
ISLAMABAD -- The Securities and Exchange Commission of Pakistan (SECP) has directed the securities brokers not to deal in securities on account of their customers without instructions of such customers.