In determining the carryover of unused credits and the effect of a merger or acquisition, federal law shall be applied to the business entities as if they were separate business entities. Any provisions under federal law that would allow separate corporations that are merged or acquired to carry forward unused credits on the surviving corporation's returns shall apply to the carryover of this credit for State purposes. Unused Credits. In a transaction involving an asset purchase, unused credits: Do not transfer from the taxpayer to the purchaser; and Shall remain with the taxpayer to whom or to which the certificate was issued. Unused credits may not be sold or purchased.