(FORTUNE Magazine) – Despite consumer jubilation, there may not be many teeth in the decision by California's Supreme Court to uphold a referendum that cuts property and casualty insurance rates by 20% -- and from their 1987 levels at that. The court's ruling exempts companies that don't earn a ''fair and reasonable return'' -- and more than 100 carriers argue that they fit that description. Most auto insurers have been losing money in California for years. State insurance commissioner Roxani Gillespie will rule on the exact interpretation of that key clause, company by company. The ruling seems to have put an end to insurers' promises that they would walk. Says August Alegi, vice president and legislative counsel at Geico: ''Since the court ruled we're allowed to make a reasonable profit, we won't leave. I haven't the slightest idea what consumer groups are crowing about. There isn't going to be any rate reduction.''F.H.K.