Just checked the IRS site. The 2012 version of form 8453 (used for tax transmittals for an e-filed return) remains unchanged in that it does not list form 4797 as one of the forms that you can attach supporting documents for. Frustrating. It looks that again, because each transaction must be shown seperately, a Mark-to-Market filer cannot file electronically. Anyone have comments on a work around? Some ideas: 1) Just dump everthing in form 8949 and then offset that as one line in form 4797. This way I could file electronically as my tax program allows almost unlimited 8949 transactions to be entered. 2) Ignore the requirement of reporting each transaction and just put in one line on form 4797 summing up everything 3) Type in summary line in form 4797 (type in "See Supporting form" in line 10a) and Use form 8453 anyway to report the form 4797 transactions and hope for the best. 4) Type in summary line in form 4797 (type in "See Supporting form" in line 10a) and not send in any supporting forms at all! (and hope for the best.) 5) Type in summary line in form 4797 (type in "See Supporting form" in line 10a) and write an open letter to the IRS where you would normally paperfile with the supporting documents 6) Just give in and not file electronically at all. Any opinions from you electronically filing Mark-to-Marketers out there? What have you done in the past?