Profitable Trade: SLV Naked Puts

Yesterday these naked puts expired worthless in a taxable account:

12/28/2011   STO   7 SLV  Dec 30 2011 25 Puts@.12                               68.66

This was a 2 day trade on $2900 in margin maintenance. Time decay was a great ally here.  They expired worthless and we earned 2.36% or 430.7% annual. I felt that precious metals had bottomed at the time I entered this trade.