40 CFR § 97.155
Banking
June 9, 2020
(a) CAIR NOX 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 NOX allowance that is held in a compliance account or a general account will remain in such account unless and until the CAIR NOX allowance is deducted or transferred under §97.142, §97.154, §97.156, or subpart GG or II of this part.