IRS Letters and Forms
Notice code 406

Notice code 406 (Default) — We disallowed your treaty exemption because you didn’t reply to our request for more information. We…

What this IRS notice code means, and what to check before you reply.

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406

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 disallowed your treaty exemption because you didn’t reply to our request for more information. We have changed your tax return accordingly.

What it usually means

406 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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