Third Rock settles for an A

Third Rock Ventures says its absence from recent series B rounds in companies it founded reflects a confluence of its focus on company building from the ground up and the desire of crossover investors to access private biotechs in or on the cusp of clinical development.

Nevertheless, the firm still aims to hold stakes of 40% or more in its portfolio companies when they go public. While it's too early to tell whether Third Rock's lack of participation in a trio of B rounds in April will result in ownership stakes that meet the goal, the ownership trend from the firm's first two funds is on an upward trajectory. ...