A supersonic business jet (SSBJ) would be a small business jet, intended to travel at speeds above Mach 1.0. Typically intended to transport about ten passengers, SSBJs are about the same size as traditional subsonic business jets. Larger commercial supersonic transports such as the Aérospatiale/British Aerospace Concorde and Tupolev Tu-144 'Charger' had relatively high costs, and high noise, low range and some environmental concerns (although these problems were less evident in Concorde than the Tu-144).

Currently the Gulfstream G650 is the fastest business jet on the market.  You can read all about the Gulfstream G650 here.