Hand signaling, also known as
arb or
arbing (short for
arbitrage), is a system of hand signals used on financial trading floors to communicate buy and sell information in an
open outcry trading environment. The system is used at financial exchanges such as the
Chicago Mercantile Exchange (CME) and the
American Stock Exchange (AMEX). The AMEX is the only U.S. stock market to permit the transmission of buy and sell orders through hand signals.