Any corporation that overpaid its estimated tax for the tax year may apply for a quick refund if the overpayment is: At least 10% of the expected tax liability. At least $500. Current Revision Form 4466 PDF Recent Developments None at this time. Other Items You May Find Useful All Revisions for Form 4466 About Publication 542, Corporations Other Current Products Related About Form 990-T, Exempt Organization Business Income Tax Return (and proxy tax under section 6033(e)) About Form 1120, U.S. Corporation Income Tax Return About Form 1120-C, U.S. Income Tax Return for Cooperative Associations About Form 1120-F, U.S. Income Tax Return of a Foreign Corporation About Form 1120-FSC, U.S. Income Tax Return of a Foreign Sales Corporation About Form 1120-H, U.S. Income Tax Return for Homeowners Associations About Form 1120-L, U.S. Life Insurance Company Income Tax Return