I have a quick question. I changed my business to an LLC this year in January 2017 so I now have an EIN number. Am I supposed to use it to file for my 2016 tax returns

[hborrero43]

or should I file with my social security number since my business was sole proprietorship in 2016?

[AmyT · Accepted solution]

You should file your 2016 return using the EIN (or, in this case, your social security number) under which you did business in 2016.

You will need to use to new EIN to report the LLC activity in 2017.

Note:  Since this is the last schedule C that you will file using your social security number, you should mark this as a "final return".