It has awarded Lex Vehicle Leasing a contract to supply up to 5,000 cars for its employees across 24 UK businesses.
The deal was arranged by Car Benefit Solutions, a company that specialises in the design, development and implementation of structured company car alternatives.
The companies involved say the new arrangement offers a 'latest generation scheme' boasting a number of innovative features designed to minimise costs arising from early termination and excess mileage. They add that it meets full compliance approval from the Inland Revenue.
Lex said it was well placed to compete for the business due to a £12 million investment in its IT infrastructure support system and added that the new contract positions it as 'one of the market leaders in the provision of innovative employee car schemes'.
A spokesman said: 'The highly bespoke nature of the contract means that only the most open and flexible system could manage and administer the agreement.'
Siemens Shared Services managing director Juergen Maier said: 'We have chosen Lex as our partner in this highly significant contract for two important and very specific reasons. Firstly, Lex's electronic trading and reporting competency is clearly ahead of its competitors, a factor that aligns closely to the Siemens innovative culture. The Lex IT capability represents a jewel in its crown.
'Secondly, Lex values its people and promotes a passion for customer service which is evident throughout every level of its business.'
Lex Vehicle Leasing managing director Jon Walden said: 'We are delighted that such a world-class organisation as Siemens has chosen to work with us. Everyone in the business is excited and inspired by this landmark contract.'
The company said the deal allows Siemens' staff to own cars in a tax-efficient way while having access to driver-support services offered by Lex, including its Lex One-Call servicing and maintenance programme, as well as online and mobile vehicle communications.