Upstairs Trade
When a trade in a listed stock is not executed through the listing exchange.
Investopedia Commentary
Historically, in an upstairs trade buyers and sellers would negotiate the price and conditions of the trade in the "upstairs" rooms of a brokerage firm. Some exchanges prohibit upstairs trading.
Related Links
Getting to Know Stock Exchanges
Markets Demystified
The Dirt On Delisting
See also: Exchange, Listed Security, Over-The-Counter - OTC