The accumulated adjustments account (AAA) is a corporate-level ledger every S corporation maintains to track income that has already been taxed to its shareholders but not yet paid out to them. It answers one question the IRS cares about deeply: when the company distributes cash, is that money coming out of profits the owners already paid tax on, or out of old C corporation earnings that have never faced the shareholder-level tax? Distributions covered by AAA come out tax-free (to the extent of stock basis). Distributions beyond it can become taxable dividends. The account lives on Schedule M-2 of Form 1120-S, and the IRS instructions ask every S corporation to maintain it, even ones that will never need it.
What goes in and what comes out
AAA starts at zero on the first day of the corporation's first S year. Each year it increases by the company's taxable income items, both the ordinary business income on page 1 of Form 1120-S and the separately stated income items that flow through on Schedule K-1. It decreases by losses, by deductible expenses, by nondeductible expenses that are not related to tax-exempt income (half of owner meals, penalties, and similar items), and by distributions.
Two asymmetries matter. First, tax-exempt income never increases AAA; it goes to a separate ledger called the other adjustments account (OAA). Second, AAA can go negative from losses, but never from distributions. A distribution can only take the account to zero. That distinction is why a company that lost money for two years and then distributes cash can produce a very different tax answer than the owner expects.
There is also an ordering rule inside a single year: income items go in first, then distributions are measured against the account, and then losses come out. A year with both profit and a large distribution uses the profit before testing the distribution, which usually works in the shareholder's favor.
When AAA decides whether a distribution is taxable
For an S corporation that has been an S corporation its whole life and has never absorbed a C corporation in a merger, AAA is bookkeeping rather than destiny. With no accumulated earnings and profits (E&P), distributions are governed by stock basis alone: tax-free up to basis, capital gain beyond it.
The account earns its keep when the company carries E&P from C corporation years. Then IRC Section 1368(c) imposes a strict ordering on every distribution: first out of AAA, tax-free to the extent of stock basis; then out of accumulated E&P as a taxable dividend; then out of any remaining stock basis as a tax-free return of capital; and finally as capital gain. A company with a thin AAA balance and fat E&P can turn what the owner assumed was a tax-free draw into dividend income on their Form 1040.
Two elections can rearrange the order. A company can elect under Section 1368(e)(3) to distribute E&P first, which is occasionally worth doing to purge E&P and escape the passive investment income rules that can otherwise tax or even terminate an S corporation holding too much investment income on top of old E&P. And when an S election terminates, the corporation gets a post-termination transition period, generally at least a year, during which cash distributions can still come out of AAA tax-free. Miss that window and the remaining AAA benefit is gone for good.
For creators and the self-employed
Most creator S corporations elected S status from day one or converted from a single-member LLC, so they have no E&P and their owners only ever need to watch stock basis. The account still has to be maintained on Schedule M-2, and keeping it accurate is cheap insurance: an acquisition, an investor's C corporation rolling in, or a revoked and re-made election can all import E&P later, and at that point a decade of clean AAA history is the difference between tax-free distributions and dividends.
The practical habit worth building is reconciling AAA to the books once a year when the 1120-S is filed. AAA is not retained earnings and it is not stock basis: retained earnings is a book number, basis is tracked shareholder by shareholder (and includes loans the owner made to the company, which AAA ignores), and AAA is its own statutory account with its own rules. The three move together in a simple year and drift apart the moment there are nondeductible expenses, tax-exempt income, or an owner loan.
Mistakes that cost money
Treating AAA as if it were basis: a distribution can clear the AAA hurdle and still be capital gain because the shareholder's stock basis ran out first. The two limits are tested separately, and the lower one wins.
Letting distributions drive the account negative on the books: only losses can take AAA below zero. Software or a spreadsheet that subtracts a distribution past zero will misstate every later year, and the error compounds silently until a sale or an audit forces a reconstruction.
Ignoring the account because there is no E&P today: reconstructing fifteen years of AAA during due diligence for a sale is expensive, and a buyer's accountants will ask for it. The Schedule M-2 balance is also one of the first places the IRS looks when it examines distributions.
Forgetting the post-termination window: owners who revoke an S election and leave cash in the company past the transition period turn their own previously taxed profits into C corporation dividends when the cash finally comes out.