the partnership was already filed, and I would like to just put the interest income that I found in the current year return. In other words, just report it, get it over with, and if the IRS finds out under audit later on then so be it. The alternative would be to notify the partners, give them amended K-1's from 2006, and tell them (4 partners) to go and file 1040X's, and I will not be a popular guy, not for the right reasons anyway! Any harsh ramifications for just putting the income in the current year? Should I label it as "Interest Income from prior period" in the spirit of full disclosure? Or just categorize as interest income and call it a day?
Each year stands on its own. You should not be reporting 2006 income on the partnership's 2012 tax return. You should, however, restate the opening balance sheet to reflect the previously earned income. It is too late to amend 2006 as the year is "closed" (being more than 3 years old. I am assuming that the omission was not intentional and merely an oversight. If I am wrong, you should seek tax counsel. Good luck.
Marty Davidoff, firstname.lastname@example.org, 732-274-1600. This answer is provided for general information only. You should seek advice from an attorney or tax professional.