Definition of 'Primary Dealer'
A pre-approved bank, broker/dealer or other financial institution that is able to make business deals with the U.S. Federal Reserve, such as underwriting new government debt. These dealers must meet certain liquidity and quality requirements as well as provide a valuable flow of information to the Fed about the state of the worldwide markets.
Investopedia explains 'Primary Dealer'
These primary dealers, which all bid for government contacts competitively, purchase the majority of Treasuries at auction and then redistribute them to their clients, creating the initial market in the process.
Some of the well-known primary dealers in the United States include Merrill Lynch, Citigroup, and Lehman Brothers.