CAT Forms Now Available Online Posted on December 17, 2020 by Karla Holland Forms for Oregon’s Corporate Activity Tax are now available on the Department of Revenue website. Go to the Revenue forms page and scroll down to Corporate Activity Tax or type “corporate” in the search box. Forms now available include: Form OR-CAT, Oregon Corporate Activity Tax Return. Form OR-CAT, Oregon Corporate Activity Tax Return Instructions. Form OR-CAT-EXT, Application for Extension of Time to File an Oregon Corporate Activity Tax Return. Form OR-CAT-V, Oregon Corporate Activity Tax Payment Voucher. Form OR-QUP-CAT, Underpayment of Oregon Corporate Activity Estimated Tax. Publication OR-CAT-BRO, Corporate Activity Tax Brochure. Schedule OR-AF-CAT, Schedule of Affiliates for Form OR-CAT. Schedule OR-EXC-CAT, Exclusions From Commercial Activity. Schedule OR-EXC-CAT, Exclusions From Commercial Activity. Worksheet OR-CAT, Instructions for calculating tax on corporate activity. Taxpayers with general questions about the CAT can email firstname.lastname@example.org or call 503-945-8005.