Prudential is one of the largest life insurance companies in the UK and has more than 13,000 employees, with a total of 25,000 worldwide.
It compared 10 outsourced fleet management providers in a tendering process before choosing a supplier for its 900-vehicle fleet.
Inchcape Fleet Solutions will be providing its maintenance management service through a dedicated Premier Service team, based at the firm's Portsmouth head office.
The maintenance management team of technical controllers will use their training and buying power to reduce downtime and get value for money from suppliers.
John Wills, fleet manager for Prudential, said: 'We were impressed by the quality of Inchcape's response. They were able to demonstrate quality service, together with tangible cost savings in a professional manner.
'We saw a number of companies during our market evaluation, but Inchcape stood out from the rest. This was underlined by excellent references from existing customers.'