A new home co-broker (NHCB) is a licensed real estate agent or broker who sells a new construction home and is paid a selling fee, or as builders call it, a 'co-broker' fee. 

A bit of history. The term, 'co-broker' as it applies to new construction, comes from the fact that homebuilders see themselves in principle as the listing broker. the listing broker and if the home or condominium is sold to a buyer who properly registered as the agent's prospect. The commission is paid the "cooperating broker." thus, the term , 'co-broker'.