a few posters mentioned FAZ, SKF and perhaps SDS
I trade mostly leveraged ETF's off the movement of SPY but only for a few pennies at at time with large volume.
I concentrate on just a few stocks (or ETF's) as stocks move different depending on volume
If your buying power is not that large perhaps as much as possible of a low priced stock like C, GE, UYG, XLF
If your loaded with dough perhaps the higher price 2 or 3X ETF's
I trade mostly leveraged ETF's off the movement of SPY but only for a few pennies at at time with large volume.
I concentrate on just a few stocks (or ETF's) as stocks move different depending on volume
If your buying power is not that large perhaps as much as possible of a low priced stock like C, GE, UYG, XLF
If your loaded with dough perhaps the higher price 2 or 3X ETF's