The tax year 2021 1120 Modernized e-File (MeF) Assurance Testing System (ATS) information is contained below. If you support these forms, you will need to contact the e-Help Desk for testing. Please monitor this page for any ATS scenario updates. TY 2021 1120 MeF ATS scenarios 1120 MeF ATS scenario 1 (Form 1120) PDF (10/27/2021) 1120 MeF ATS alt scenario 1 (Form 1120) PDF (10/27/2021) 1120 MeF ATS scenario 2 (Form 1120) PDF (10/27/2021) 1120 MeF ATS scenario 3 (Form 1120) PDF (10/27/2021) 1120 MeF ATS scenario 4 (Form 1120) PDF (10/27/2021) 1120S MeF ATS scenario 5 (Form 1120S) PDF (10/27/2021) 1120S MeF ATS scenario 6 (Form 1120S) PDF (10/27/2021) 1120S MeF ATS scenario 7 (Form 1120S) PDF (10/27/2021) 1120S MeF ATS scenario 8 (Form 1120S) PDF (10/27/2021) 1120F MeF ATS scenario 9 (Form 1120F) PDF (10/27/2021) 1120S MeF ATS scenario 10 (Form 1120S) PDF For information and questions regarding ATS, please contact the e-Help Desk at 866-255-0654. Modernized e-File (MeF) Assurance Testing System (ATS) updates page Tax year 2021 1120 MeF schemas and business rules page