Six tax protesters were convicted in St. Paul, Minn., of conspiracy to defraud the U.S. government by setting up a system of so-called "warehouse banks" that did not report customers' transactions. The six were accused of setting up the private institutions in at least three states to conduct secret financial transactions and thus conceal their income from the Internal Revenue Service. The unchartered warehouse banks dealt with account holders by number instead of names, kept no records and emphasized privacy on transactions made in cash or commodities, the government said. Federal law requires reporting of cash financial transactions that exceed $10,000. Each defendant faces a maximum of five years in prison on one count of conspiracy to defraud the government. The six were members of the Denver-based National Commodity and Barter Assn., founded in 1980. Defense attorneys said they planned to appeal.