I sold a seller financed mortgage note at a loss. How do i claim loss?

[Critter-3]

You were reporting this sale as an installment on form 6252?     Or were you just holding the note and reporting the interest on your return ?  

[Roger21]

I held a regular mortgage note on the sale of my home, not an installment sale.  I claimed interest as income for the 4 years that I held the note.  I did not report this sale on 6252

[Critter-3]

If this was a note on the sale of a personal residence where none of the sale was taxable then "selling" the note for less than what you were owed  is not a deductible loss.  You did not lose anything ... in the long run you just sold your house for less.