They play a key role in marketing new issues of money market instruments and in providing secondary markets where outstanding issues can be sold prior to maturity. Dealers use RPs to finance their inventories of securities. They also act as intermediaries between other participants in the RP market by making loans to those wishing to borrow in the market and borrowing from those wishing to lend in the market. Brokers match buyers and sellers of money market instruments on a commission basis. They play a major role in linking borrowers and lenders in the federal funds market.
Brokers are also active as intermediaries in trades between dealers in various of other markets.
The Federal Reserve is a key participant in the money market. They control the supply of reserves available to banks and other depository institutions primarily through the purchase and sale of Treasury bills, either outright in the bill market or on a temporary basis in the market for repurchase agreements. The Federal Reserve is able to influence the federal funds rate by controlling the supply of reserves. Movements in this rate, in turn, can have pervasive effects on other money market rates. The Trading Desk frequently engages in billions of dollars of open market operations in a single day.