Minnesota could be on the hook for $700 million in refunds should it lose a case pending in state tax court. The $700 million figure -- which would be more than half the state's annual corporate franchise tax collections and about 2 percent of its biennial general fund budget -- was given in court papers in November by state Solicitor General Alan Gilbert, who is representing the state Revenue Department in an appeal brought by Dallas-based Kimberly-Clark Corp. Even if Gilbert's estimate is on the high side, the state's potential liability is "a big deal," said Richard Pomp, a professor at the University of Connecticut School of Law and a former consultant to the Multistate Tax Commission.