RYDEX DYNAMIC FDS INVERSE S P 500 2X MUTUAL FUNDS USMF - What does RYDEX DYNAMIC FDS INVERSE S P 500 2X MUTUAL FUNDS USMF mean? - What does RYDEX DYNAMIC FDS INVERSE S P 500 2X MUTUAL FUNDS USMF stand for? - RYDEX DYNAMIC FDS INVERSE S P 500 2X MUTUAL FUNDS USMF meaning