U.S. Income Tax Return for Regulated Investment Companies. This form is used to report the income, gains, losses, deductions, and credits, as well as to figure the income tax liability of a regulated investment company (RIC) as defined in IRS section 851. This form is filed by a domestic corporation that meets certain conditions should it elect to be treated as a RIC for the tax year, or has made an election for a prior tax year and the election has not been terminated or revoked.