31 C.F.R. § 50.112
(b) Except as provided in paragraph (e) of this section, if Treasury estimates that aggregate insured losses may exceed the cap on annual liability for a calendar year, then Treasury will determine a PRLP. The PRLP applies to insured loss payments by insurers for insured losses incurred in the subject calendar year, as specified in § 50.113, from the effective date of the PRLP, as established by Treasury, until such time as Treasury provides notice that the PRLP is revised. Treasury will determine the PRLP based on the following considerations:
(e) If Treasury estimates based on an initial act of terrorism or subsequent act of terrorism within a calendar year that aggregate insured losses may exceed the cap on annual liability, but an appropriate PRLP cannot yet be determined, Treasury will provide notification advising insurers of this circumstance and, after consulting with the relevant state authorities, may initiate the action described in either paragraph (e)(1) or (2) of this section.
(2) Determine an interim PRLP.