I have read that an observant Jew who owns a business is obliged to keep the business kosher for Passover as well as his own home.
That being an obvious problem for a food-related business :) a clever solution has apparently arisen -- the Jewish business owner will sell his business (or at least the non-KfP items) to a non-Jew for the duration of Passover. Apparently (from what I've read) the sales contract has to be real in the sense that it is truly legally binding. It's often in the form of "I'm selling you the business for $X (where $X is a legit number) but you only have to pay me $1 today. The balance is due in nine days and if you don't pay in full the business reverts to me."
While the contract is legally-binding in the sense that if the "buyer" really forked over the balance he would in fact truly own the business, both sides enter into the contract with the expectation that the balance will not be paid.
So I'm wondering what the tax treatment of that is. Is it ignored for tax purposes (and if so, on what grounds)? Is it treated like a some sort of failed installment sale where virtually zero payment was ever received? Something else?