Profitable Trade: GDX Naked Puts

Today in a taxable account I closed the following transaction for a profit:


01/20/2012    STO 4 GDX Feb 18 2012 49 Puts @.57                  214.89
02/02/2012    BTC 4 GDX Feb 18 2012 49 Puts @.03                  -12.05

In this trade we made $202.84 in 13 days on margin maintenance of ~ $3200.00. This equates to a return of 6.34% or 178% annual. I could have waited for these puts to expire worthless but we had drained most of the profit out of the trade and there was no commission at exit. I'm going to be looking for other, more profitable opportunities in this account.