wirehouse
A major brokerage company, generally nationwide, with multiple branches.
Ten years ago, the Wall Street wirehouse brokerage firm seemed unassailable – part of the very firmament underpinning the entire investment industry from coast to coast.
A brokerage company with a telegraph line, telephone line, or electronic communication network.
obsolete
The so-called ‘wire house’ …is a product of the boom times.
Where it comes from
1904, wire + house (“company”), from earlier private-wire house (1894). Originally referred to brokerage companies that owned or leased telegraph lines, so that market information could be transmitted more quickly. Later generalized to “major brokerage”. Wirehouses are now defined by that they have a direct access to "Fed-Fund Wires", which is the system in which all banks and only the big brokerage houses can "wire" money directly from one account to another. Smaller brokerage firms do not have their own wire line, but need to send transactions by transmitting them through a bank's wire system.
Adapted from the Wiktionary entry wirehouse (CC BY-SA 4.0).