The two groups claim the amalgamation will mean a 'stronger offering' for manufacturers and dealers.
John Bailey, chief executive of Manheim Europe, said: 'By bringing these two companies closer together, we provide an unrivalled offering in the marketplace. The breadth of services available within the Manheim family demonstrates the strength of the group and we believe an integrated approach puts us in an unrivalled position to add value to our customers' businesses.'
Several appointments have been made as a result of the affiliation. Mike Pilkington has been made managing director of Portfolio Europe but will continue as managing director of Vehicle Remarketing Solutions.
He will manage both companies as individual businesses but will also develop joint offerings from the two groups.
Andy Henshaw is to remain chief executive officer at Portfolio Europe and will focus on developing the direction of the company.
Pilkington said: 'We are taking a strategic view of how we can combine the latest technology with leading edge vehicle wholesaling and retailing strategies to make a difference to our customers' businesses.'
The two groups will provide a range of remarketing services and already share a number of customers, including MG Rover, Skoda and Volkswagen.
Portfolio Europe currently provides retail marketing support for manufacturers and dealers including photography and data collection. Vehicle Remarketing Solutions offers de-fleet, reconditioning and remarketing services.
Portfolio Europe believes the internet boom will drive expansion of the group.
Henshaw said: 'Half of consumers use the internet as a first point of call when they seek to purchase a new or used car and this continues to grow. Portfolio has seen its business triple over the last few years in line with this trend.'