11 USC § 549. Postpetition transactions
(a) Except as provided in subsection (b) or (c) of this section, the trustee may avoid a transfer of property of the
(1) that occurs after the commencement of the case; and
(A) that is authorized only under section 303(f) or 542(c) of this title; or
(B) that is not authorized under this title or by the court.
(b) In an involuntary case, the trustee may not avoid under subsection (a) of this section a transfer made after the commencement of such case but before the order for relief to the extent any value, including services, but not including satisfaction or securing of a debt that arose before the commencement of the case, is given after the commencement of the case in exchange for such transfer, notwithstanding any notice or knowledge of the case that the transferee has.
(c) The trustee may not avoid under subsection (a) of this section a transfer of an interest in real property to a good faith purchaser without knowledge of the commencement of the case and for present fair equivalent value unless a copy or notice of the petition was filed, where a transfer of an interest in such real property may be recorded to perfect such transfer, before such transfer is so perfected that a bona fide purchaser of such real property, against whom applicable law permits such transfer to be perfected, could not acquire an interest that is superior to such interest of such good faith purchaser. A good faith purchaser without knowledge of the commencement of the case and for less than present fair equivalent value has a lien on the property transferred to the extent of any present value given, unless a copy or notice of the petition was so filed before such transfer was so perfected.
(d) An action or proceeding under this section may not be commenced after the earlier
(1) two years after the date of the transfer sought to be avoided; or
(2) the time the case is closed or dismissed.