private-wire house

Etymology
1894, due to these brokerage companies owning or leasing telegraph lines (which occurred since 1873), so that market information could be transmitted more quickly.

Noun

 * 1)  A brokerage company with a telegraph line, telephone line, or electronic communication network.
 * 2) * 1894, “Chicago Was Afraid of Wall Street”, , February 10, 1894, page 2:
 * All the private-wire houses were active on the selling side, those most talked of in connection with the Wall Street bull interest being the most active.