Large cap biotechs were the only market cap segment to end 4Q12 in the black, finishing up 1% to post a 26% gain on the year. Small caps brought up the rear in 4Q, but only the micro-caps closed out 2012 in the red, down 5% on the full year.

The $5 billion-plus tier outperformed all segments for the year (see "Results by Market Cap").