40 CFR § 97.255 - Banking.

(a) CAIR SO2 allowances may be banked for future use or transfer in a compliance account or a general account in accordance with paragraph (b) of this section.

(b) Any CAIR SO2 allowance that is held in a compliance account or a general account will remain in such account unless and until the CAIR SO2 allowance is deducted or transferred under § 97.254, § 97.256, or subpart GGG or III of this part.