A summary of Southern California-related business litigation developments during the past week.

Allstate Challenges Prop. 103: Allstate Insurance Co. filed suit in Los Angeles Superior Court on Thursday seeking a ban on the enforcement of emergency Proposition 103 regulations and calling for a return to the previous rate-setting system. Allstate’s suit says the regulations created by Commissioner Roxani Gillespie violate the state Constitution and were not supported by substantial evidence before being approved. (Filed Jan. 4, 1990 Case No. C748209)