28 U.S.C. § 3305 — When transfer is made or obligation is incurred

(1) A transfer is made for (A) real property, other than a fixture but including a seller's or purchaser's interest under a sale contract, when it is perfected enough that a good-faith purchaser from the debtor could not obtain a superior interest under applicable law; and (B) other property or a fixture, when it is perfected enough that a simple-contract creditor could not obtain, outside this subchapter, a superior judicial lien. (2) If applicable law permits that perfection but it was not completed before a relief action or proceeding began, the transfer is treated as made immediately before the action or proceeding began. (3) If applicable law does not permit that perfection, the transfer is made when it becomes effective between the debtor and transferee. (4) A transfer is not made until the debtor has rights in the transferred asset. (5) An obligation is incurred (A) when an oral obligation becomes effective between the parties, or (B) when a writing signed by the obligor is delivered to or for the obligee.