financial economics, monetary economics, financial system, money, market, money market instruments, denomination, default risk, T-Bills, Fed funds, repos, commercial paper, negotiable CDs, banker's acceptances, risk-free, default-free, inflation risk, exchange risk, OMO, open-market operations, bid, competitive bid, non-competitive bid, securities dealers, primary dealers, spread, bid-ask spread, buy-sell spread, secondary market, registered security, bearer security, ledger, Fedwire, book-entry system, discount, discount yield.