This form shall be filed as required by §300.303 of this chapter with the trustee in a proceeding under section 5 of the Act by a broker-dealer who executed transactions out of which arose open contractual commitments, as defined by §300.300(c) of this chapter, with the debtor in the proceeding. The form shall be used to report all the fails to deliver, as defined by §300.300(b) of this chapter, that were open on the filing date, as well as any subsequent closeouts. This form shall accompany the form described in §300.300a.