The IBD 100 had a good week last week, climbing 2.5% overall, and last week's big gainer, SOL, bagged 22%. Last Friday it was pulling back right to support, giving a really nice buying opportunity, and took off from there.
EXLS was the biggest decliner last week, and looking at the chart, I'm not quite sure why it was on the 100. It looks like it had an earnings miss on Wednesday, but the action on Friday probably would have shaken me out of it.
GFA was the second biggest decliner and is a good example of a failed breakout. I normally use trailing stops when I buy breakouts, so I probably would have been stopped out on the reversal.