Among biotech-focused hedge funds, Healthcor Management opened a new 600,000 share position in Idenix in the fourth quarter. Noteworthy Idenix sellers in the fourth quarter include mutual fund giant Fidelity, which shed 1.5 million shares and Baker Brothers, which exited the stock entirely by selling 572,000 shares. Achillion Pharmaceuticals ( ACHN), another developer of oral hepatitis C drugs, is also grabbing its share of takeout chatter. Three investors of note -- West Coast hedge fund Tang Capital, Chicago's Citadel Advisors and Canadian investors Sectoral Asset Management all opened significant new positions in Achillion during the fourth quarter. --Written by Adam Feuerstein in Boston. >To contact the writer of this article, click here: Adam Feuerstein. >To follow the writer on Twitter, go to http://twitter.com/adamfeuerstein. >To submit a news tip, send an email to: email@example.com. Follow TheStreet on Twitter and become a fan on Facebook.