Manheim will continue to remarket vehicles for Santander Consumer Finance for the next three years.
The two businesses have extended their contract, which began in 2002.
Shaun Deacon, head of Arrears Management at Santander Consumer Finance, said: "This renewal signals the strength of our on-going partnership with Manheim, we've been working together for 16 years and greatly value their expertise, attention to detail and dedication to making our sales a real success."
The partnership extension, which started this month and will run until February 2021, will see vehicles from Santander Consumer Finance continue to pass through Manheim's auction lanes in: Bristol, Colchester, Manchester, Mansfield and Washington.
Peter Bell, managing director of Manheim, added: "This is fantastic news that further cements our relationship with Santander Consumer Finance and we are proud to continue working together.
"The contract extension is testament to the hard work and professionalism that Manheim teams provide on a daily basis to its partners, and we are very much looking forward to continuing our relationship with the team at Santander Consumer Finance."