Why does my CPA need a basis schedule for my S-corp?

An S-corporation shareholder's basis measures what the owner has invested and what has been taxed and distributed; losses are deductible only up to basis, and distributions above basis are taxable. Loans from the shareholder to the company create debt basis only if they are real, documented loans. The IRS requires a basis schedule with the personal return in several situations, and repayments of undocumented loans are indefensible without one.

Key points

An S-corporation shareholder's stock basis starts with capital contributed, rises with pass-through income and further contributions, and falls with losses and distributions.
Losses passed through from an S-corporation are deductible only up to the shareholder's stock and debt basis; the excess is suspended and carried forward.
Distributions from an S-corporation are tax-free only up to stock basis, and any excess is taxable, generally as capital gain.
A shareholder loan creates debt basis only when it is a documented, direct loan from the shareholder to the corporation with a note and repayment terms.
Form 7203 must accompany the personal return when the shareholder claims a loss, receives a distribution, disposes of stock, or is repaid a loan.

What is S-corporation shareholder basis?

Basis measures a shareholder's investment in the company as adjusted over time. It starts with what the shareholder put in, rises with the income the company earns and passes through on Schedule K-1 and with any additional capital contributed, and falls with losses passed through and with distributions taken. The adjustments follow the ordering rules in section 1367.

Because an S-corporation's income is taxed to the shareholder as it is earned, whether or not it is withdrawn, basis is the running record that prevents the same dollars from being taxed twice and tracks what has already been taxed. It is one of the least understood numbers in a small business and one of the most consequential, because it silently controls whether losses are deductible and whether money taken out is taxed.

Why are losses and distributions limited by basis?

Two rules give basis its bite. First, under section 1366, losses are deductible only up to the shareholder's basis. If the company passes through a loss larger than basis, the excess is not lost but is suspended: it cannot be deducted now and carries forward until there is enough basis to absorb it. Owners who assume every reported loss shelters other income are often wrong for exactly this reason.

Second, distributions are tax-free only up to stock basis. A distribution larger than basis produces taxable income on the excess, generally treated as gain from the sale of stock. Neither rule can be applied correctly without an accurate basis schedule, which is why the CPA asks for it before finalising the personal return.

When does a shareholder loan create debt basis?

Money a shareholder lends directly to the company can create debt basis, which allows losses to be deducted beyond stock basis. This only works if the loan is a real, documented loan: a signed note, a stated interest rate, a repayment expectation, and actual transfers flowing directly from the shareholder to the corporation. Informal advances, or amounts routed through another entity the shareholder owns, frequently fail to create debt basis.

The failure surfaces at the worst moment. When a loan that gave the shareholder debt basis is repaid after that basis was reduced by losses, the repayment itself can produce taxable income. Without documentation of the original loan and a basis schedule tracking the reductions, the position cannot be defended, and the repayment is taxed in full.

What happens if basis was never tracked?

The IRS requires Form 7203, the shareholder stock and debt basis computation, to be attached to the personal return when the shareholder claims a loss, receives a distribution, disposes of stock, or receives a loan repayment. That requirement is why the schedule needs to be maintained every year rather than reconstructed when one of those events occurs.

The honest limit is that reconstruction is expensive and often produces a weaker number. Rebuilding years of basis means retrieving every prior Schedule K-1, every capital contribution, and every distribution back to the day the S election took effect, and any year with missing records leaves a gap the shareholder has to estimate. Keep the basis schedule current, document shareholder loans at the time they are made, and check basis before taking a large distribution or claiming a large loss.