Yip, depends on your gearing. A 10 times gearing means in Lehman terms that you purchase a contract at R10k for instance but your total exposure is R100k, meaning your R10k can either make or lose you R100k - be very careful.
I was long on most financials a few weeks back (very cheap and underbought IMO) and the market turned in my favour last week (overbought) so I started isolating a few who I thought would trade erratically and took a bit of a gamble on Standard Bank, First Rand and Nedbank Group who traded rather strangely yesterday IMO. I stayed long for a few days then shorted a few as a gamble, then just followed the market yesterday. Was a bit of educated guess work with some statistical analysis.