Kansas City, Mo. ? A federal judge has agreed to limit the number of potential class members in an ongoing racketeering case against tax preparer H&R Block Inc., the company said in a securities filing Friday.

Plaintiffs sued the Kansas City, Mo.-based company in 1998, claiming that its use of high-interest tax refund loans to customers was illegal and sought to include 17 million customers who had received loans over a 13-year period.

U.S. District Judge Elaine Bucklo in Chicago last week granted partial summary judgment for H&R Block, agreeing that the four-year statute of limitations for racketeering cases limited the range of customers to between 1995 and 1996, shrinking the potential class size to 1.7 million customers.

Bucklo earlier had limited the class size to before 1997 when the company began requiring that loan disputes go through arbitration.

The racketeering case is scheduled to go to trial May 15.