Your question: In TurboTax for prior years, where would the basis be input and attached?
This information was not entered into TT in previous years. My S Corp's CPA provides cost bases sheet for each shareholder with K1. But, that information may not be 100% accurate. Each shareholder is responsible to calculate his/her cost bases every year using IRS instructions.
Only difference this year is that we need to provide that cost bases calculation for 2021 to IRS with our personal return in From 7203.
It is OK if you have not calculated cost bases for all previous years. Print a copy of 7203 and use that starting with 1st year of your S Corp. if you have only few yeas it may be easy, if you have 10/20 year old S Crop you may have to work hard to calculate for all those years... but trick is you need to start from the 1st year you owned this stock and go all the way to 2021. good luck!
