brokerage

This term encompasses both the professional activity of mediating transactions and the physical or legal entity that performs this service. It carries a strong connotation of financial intermediation, typically associated with high-stakes markets like stocks, bonds, or luxury real estate.

When referring to the fee, the word functions as a specific financial charge. While the word is generally countable when referring to firms, it is uncountable when referring to the general profession or the act of brokering.