A form 1099-S is required when sales proceeds over $250,000.

I don't think this is a valid statement.

this transaction is required to be reported on the tax return if form 1099-S was issued.

I KNOW this isn't a valid statement

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I report all sales of real estate on F.8949 > Sch D, even the sale of a personal residence (despite the fact the IRS instruction say it's not necessary..) to avoid future love letters from the IRS.  YMMV.