Regulators are implementing new price bands within which shares on U.S. equity exchanges are allowed to trade. Regulators are also testing fresh restraints that will suspend stock, options and index futures should the Standard & Poor's 500 index take a significant dive. Both programs are set to run for one year. SIFMA and CME Group asked the Securities and Exchange Commission to allow the triggering of marketwide restrictions if many individual stocks are suspended. The market participants are concerned that the situation could affect index calculations. The SEC said it will be taking comments about the programs as they are tested.