Pension Fund Buys 5.4% Stake in Tokos

The state of Wisconsin Investment Board has purchased a 5.4% stake in Tokos Medical Corp., the Santa Ana company that makes and distributes a device to help detect the onset of premature labor. The investment board, which manages pension funds for Wisconsin state employees, purchased the stake between Oct. 29 and Dec. 3 for $15.20 to $18.37 a share, according to a Securities and Exchange Commission filing.