Miss. Code § 27-19-141
In case any person, other than a dealer or agent, shall sell, assign or transfer any vehicle to another person, the person acquiring such vehicle shall register the vehicle with the county tax collector of his residence or the State Tax Commission within seven (7) working days after such sale, assignment or transfer and pay the annual privilege license taxes. The seller or transferor shall remove the license plate from the vehicle and retain same. Such license plate must be surrendered to the issuing authority with the corresponding tax receipt if required, and credit shall be allowed for the taxes paid for the remaining tax year on like privilege or ad valorem taxes due on another vehicle owned by the seller or transferor, or by the seller's or transferor's spouse or dependent child. Privilege taxes on vehicles registered in excess of ten thousand (10,000) pounds gross vehicle weight, apportioned vehicles, rental and commercial trailers and buses, shall be considered like taxes only for vehicles registered in excess of ten thousand (10,000) pounds gross vehicle weight, apportioned vehicles, rental and commercial trailers and buses. Privilege or ad valorem taxes on vehicles with a gross vehicle weight of ten thousand (10,000) pounds or less shall be considered like taxes only for vehicles with a gross vehicle weight of ten thousand (10,000) pounds or less. If the seller or transferor does not elect to receive such credit at the time the license plate is surrendered, the issuing authority shall issue a certificate of credit to the seller or transferor, or to the seller's or transferor's spouse or dependent child, or to any other person, business or corporation, at the direction of the seller or transferor, for the remaining unexpired taxes prorated from the first day of the month following the month in which the license plate is surrendered. Any credit allowed for taxes due or any certificate of credit issued may be applied to like taxes owed in any county by the person to whom the credit is allowed or by the person possessing the certificate of credit. No credit, however, shall be allowed on the charge made for registration fees and any tag fees. Such license plates surrendered to the tax collector shall be retained by him, and in no event shall such license plate be attached to any motor vehicle after being surrendered to the tax collector, nor shall any license plate be transferred from one (1) motor vehicle to any other motor vehicle. Certificates of credit shall be designed and furnished by the commissioner.
The credit authorized by this section shall not apply to trailers or semitrailers subject to the tax levied in Section 27-19-18.
Miss. Code § 27-19-141