The Internal Revenue Service said Monday that its Modernized eFile system has begun accepting business tax returns.

In an email to tax professionals, the IRS said its MeF system successfully opened Monday morning, January 7, at 9:00 am EST and is now operational for the following business tax returns:

• Fiscal year returns with a year ending prior to 12/31/2012
• All 2011 tax year and 2012 fiscal year business returns, including Form 1120 series
• 2012 tax year Form 2290, Heavy Highway Vehicle Use Tax Return
• 2012 tax year Form 7004, Application for Automatic Extension of Time to File Certain Business Income Tax, Information and Other Returns
• Form 8868, Application for Extension of Time To File an Exempt Organization Return (omitted from previous listing)

The IRS plans share additional information when it can accept the remaining tax year 2012 business forms as soon as it becomes available.

It cautioned that filers should use https://la.www4.irs.gov/a2a/mef/ for ATS and Production returns, and only use https://la.alt.www4.irs.gov/a2a/mef/ for troubleshooting when advised by the IRS to do so.