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Notice code 121 (Default) — We changed the amount of business income or loss on page 1of your tax return because there was an er…
What this IRS notice code means, and what to check before you reply.
What to do next
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121
Read the notice carefully and note any deadline. Gather returns, notices, and payment records. Book a free strategy session before responding if the amount is large, unclear, or collection language appears.
What the IRS language says
We changed the amount of business income or loss on page 1of your tax return because there was an error on Schedule C/C-EZ, Profit or Loss From Business. The error was in the: - computation of the net profit or loss on Schedule C/C-EZ and/or - transfer of that amount to page 1 of your tax return.
What it usually means
121 is in our IR Manual catalog. Official wording is dense — we translate it for business owners and individuals and map realistic next steps.
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