Maybe I can explain it this way. If you prepare your tax return, and you owe money, you mail your tax return to one of IRS's lock boxes.

If you have a refund or owe no taxes, you mail it to the address where refunds are processed.

Okay; this is agreeable — based on the information on the back cover of the IRS Form 1040 instructions. One address is used when the taxpayer is writing the IRS a tax payment check, and another address is used when the taxpayer is not writing the IRS a tax payment check.

Using the above as a guideline, IRS considers a $0 gain/loss the same category as a gain as there are only wash sale rules for losses. And since a $0 gain/loss clearly is not a loss, then it has no exception is falls into the same pot as a gain.

It seems to me to be exactly the opposite. If a taxpayer were to have a net income loss during a tax year, then he/she would (generally) receive a refund; on the other hand, if a taxpayer were to have a net income gain during a tax year, then he/she would (generally) owe money to the IRS. So, since the mailing address is the same between the tax refund case (with a net income loss) and the zero tax case, it follows that zero is categorized with loss, not with gain, for this particular situation with tax return mailing addresses.

In other words, the tax-return-mailing-address owe vs. refund situation is not comparable to the capital gain vs. capital loss situation, where for the latter situation, I had eventually concluded from IRS Pub. 550 on page 42 that zero is considered to be in a category of its own — not a loss, but not a gain either. Hence, zero cannot be a wash sale since wash sales can never apply to a non-capital-loss sale.

I hope this dead horse is now buried.

The horse was apparently resuscitated for a moment, but finally I think that it can now rest in peace.