Basis in action: why getting this right changes everything

A client takes a distribution from their S corporation and somewhere in the paperwork, the numbers don't add up. Or a partner claims a loss that looks perfectly reasonable on the surface, but when the IRS comes knocking, the documentation just isn't there. In most of those moments, the real problem isn't the transaction itself. It's basis. 

Basis is one of those concepts that sits quietly in the background of every S corporation return and every partnership filing and yet it drives some of the most consequential outcomes in tax practice. Get it right and your client's deductions stand. Get it wrong, and you're explaining disallowed losses and surprise gain recognition to someone who trusted you to get ahead of it. The good news is this: basis isn't mysterious. It follows the rules. It moves in a specific order. It tells a story, and once you know how to read that story and document it cleanly, your returns are stronger and your exam exposure drops significantly. 

What basis actually does 

For S corporation shareholders, stock basis absorbs income, losses and distributions throughout the year. Debt basis comes into play when stock basis hits zero and a shareholder has personally loaned money to the corporation. The order in which you apply increases and decreases isn't optional; it's governed by §1367 of the Internal Revenue Code (IRC), and the sequence matters more than most practitioners realize. 

For partners, outside basis works similarly but follows its own path under §752. Liability allocations add complexity that stock basis simply doesn't have. When a partnership takes on debt or shifts liabilities between partners, those changes affect outside basis immediately and if you're not tracking them, you're guessing.  

Where things go wrong 

The most common errors aren't dramatic. They're quiet. A loan repayment treated as a distribution. A loss allowed in a year when basis had already bottomed out. A Schedule K-1 item that never made it into the workpaper. These are the kinds of mistakes that feel minor in the moment and become significant on exams. 

The IRS knows where to look. Examiners are trained to pull basis calculations and test whether the math holds up. When a practitioner can hand over a clean, year-by-year workpaper that ties every Schedule K-1 line to the return, the examination tends to go more smoothly. When they can't, it tends to go poorly. 

The fix is documentation 

Tracking basis doesn't require a complicated system. It requires consistency. You need a workpaper that opens with a beginning basis, walks through every increase and decrease in the correct order, accounts for loan activity and liability shifts, and closes with an ending balance that flows directly into next year's return. Do that every year, for every affected shareholder or partner, and you've built something the IRS respects. 

The challenge is knowing exactly which items go where, what triggers a basis adjustment under the code and how to handle the edge cases that real clients bring through the door. 

Keep going  

If you want to work through the mechanics with structured examples, ordering rules and a framework for building workpapers that hold up, NATP's Basis in Action online training was built for exactly that. The instructor-led session will take place on July 29 from 9:00 a.m. to 12:30 p.m. CT.