It stands for reduced tick spread; an interest rate futures calendar spread which involves buying near-month futures and selling far-month futures at a reduced tick interval from that of its component outrights. For example, on the CBOT, the following products trade as RTS instruments: 30-year U.S treasury bond futures, 10-year U.S treasury note futures, 5-year U.S treasury note futures, 30-year interest rate swap futures, and 5-year interest rate swap futures.