You probably should. If you do not report that on line 16a on the 1040 form with the word ROLLOVER next to it, the IRS computer that checks tax returns against the 1099-R that they receive from the issuer will assume that you kept the money and will bill you for tax on the entire box 1 amount. They will not assume that it was rolled over unless it is on your tax return.
You can also just wait for the CP2000 letter from the IRS (takes about a year) and answer the letter with the information that it was rolled over.
To amend your 2015 tax return:
-- First, wait to see if your return has been accepted or rejected by the IRS or state.
-- If rejected, you can correct and re-send your return.
-- If accepted you should wait until your return has been processed and you receive your refund or conformation that any tax due has been paid. (If you file an amended return while you first return is being processed it can cause extended delays for both returns if two returns are in the system at the same time). In addition, if the IRS makes any change on your original return, you might end up having to amend the amendment – a sticky process that can take a year or more).
-- Then you can start the amend process.
-- Amended returns can only be mailed - allow 16 weeks (4 months) for processing.
See this TurboTax FAQ for help with amending:
https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filed
You can check the status of your mailed amended return at this link but allow 3 weeks after mailing before checking.
http://www.irs.gov/Filing/Individuals/Amended-Returns-%28Form-1040-X%29/Wheres-My-Amended-Return-1
**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.**
