I am thinking about it. I think 6-7% stop-loss limit are most people's settings, however, it need to be adjusted by volatility of the underneath securities.
cobra has an article about it, need to search it, and re-read it.
Cummins [CMI 90.84 -1.30 (-1.41%) ] - The heavy-equipment manufacturer lowered its full-year 2012 revenue guidance, sending shares sharply lower in extended-hours trading. In addition, the company said it plans to cut 1,000 to 1,500 employees by the end of the year。