If
1. cut 0.25, mkt tumble because mkt will be disappointed
2. cut 0.50, mkt will up , but not much, thats mkt expectation range
3. if cut 0.75, mkt will up a lot because mkt tends to believe that FED really intend to solve the liduidity problem amongst banks, and willing to act more if necessary
also ps watch the statement thereafter if any hints coming as well