Stiff penalties will be imposed on tax advisers who do not promptly give the Internal Revenue Service a required list of those they advised on big tax shelter transactions, IRS says in proposed rules (REG-160873-04). The development comes as IRS continues to crack down on abusive shelters both in audits and in the courts. The rules call for a penalty of $10,000 a day on material advisers to “reportable transactions” who do not provide IRS a list of their so-called advisees within 20 business days of a written request.