Section 121 exclusion

[Black Bart]

Is there any rule against using this on an amended return if it was not on the original?

[BOB W]

Bart

I did not read or hear anything about "only available" on a timely filed return.

[Black Bart]

Thanks, Bob

.............

[George Boutwell]

How far back do you want to amend?

Is there any rule against using this on an amended return if it was not on the original?

From IRS Publication 523:

You can choose not to take the exclusion by including the gain from the sale in your gross income on your tax return for the year of the sale. This choice can be made (or revoked) at any time before the expiration of a 3-year period beginning on the due date of your return (not including extensions) for the year of the sale.

[jainen]

same time period

>>a 3-year period beginning on the due date of your return<<

Note that this is not exactly the same time period allowed for amending returns, so the answer to the question in the original post is "maybe."