ST. PAUL— Minnesota could be on the hook for $700 million in refunds if the state loses a case pending in state tax court, according to a court filing.

The case involves how multistate corporations calculate tax liability in Minnesota and is scheduled to be heard later this month.

State Solicitor General Alan Gilbert gave the $700 million figure in court papers in November, the St. Paul Pioneer Press reported. Gilbert is representing the state Revenue Department in an appeal brought by Dallas-based Kimberly-Clark Corp.

Even if Gilbert’s estimate is high, Minnesota’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.

“Whatever the actual dollars are, it’s a lot of money,” Pomp said.

Kimberly-Clark is asking for $1.2 million plus interest. The maker of paper-based consumer products says it should have been able to use a different formula for calculating tax liability in 2007-09 that would have saved it money.

But Kimberly-Clark is a test case for seven other appeals from multistate corporate taxpayers that raise the same issue. The total sought in those eight cases is more than $27 million.

In the November filing, Gilbert told the court that the stakes could be higher.

Taxpayers had filed roughly $155 million in refund claims as of October, Gilbert said, and the state estimates claims for tax years up to and including 2012 “could be as much as $700 million.”

The $700 million figure would be more than half the state’s annual corporate franchise tax collections and about 2 percent of its two-year general fund budget.

Neither the Revenue Department nor attorneys for Kimberly-Clark agreed to talk about the case to the newspaper.

The conflict is over the validity of the state of Minnesota’s elimination in 1987 of an option for multistate businesses to use an alternate tax formula.

According to the state, Kimberly-Clark has no right to have its taxes calculated under a multistate formula that Minnesota abandoned in 1987. The company claims that formula remained a viable choice for the years it’s seeking refunds.

The Minnesota Tax Court has scheduled a hearing March 19.