"i left this dept in 2015 so why now"
I assume you mean you left that job. Did you have a 401(k) with the company?
Even if you did not cash out the 401(k) when you left, many company plans provide that they will automatically roll the 401(k) into an IRA in your name if you do not cash the plan out in a year or two. If that happened, then they would have sent a 1099-R showing the rollover. That would not be taxable if reported on your tax return, but failing to report it can result in the IRS assuming that you took the money. (Just a guess).
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
