Final answer:
The FOMC deals with primary dealers, which are financial institutions, during open market operations to influence bank reserves and the federal funds rate.
Step-by-step explanation:
When the Federal Open Market Committee (FOMC) executes open market operations, it conducts transactions primarily with major financial firms or groups known as primary dealers. Primary dealers are a select group of banking and financial institutions that have a relationship with the Federal Reserve and are obligated to participate in the open market operations of the FOMC. These dealers provide a ready market for the purchase and sale of U.S. Treasury securities, which are often used in open market operations to influence the level of bank reserves and the federal funds rate.