Although two segments lost ground in 4Q13, all of biotech's market cap groups finished 2013 in the black.

Large caps valued at more than $5 billion led the way in the fourth quarter, tacking on 10%. The top tier gained 48% for the year, second only to the $1-$4.9 billion group, which closed up 51% in 2013 (see "Results by Market Cap, A11).