Passage: On 12 March 2007, a consortium led by Prodrive chairman David Richards purchased Aston Martin for £475 million (US$848 million). The group included American investment banker John Singers and two Kuwaiti companies namely Investment Dar and Adeem Investment; Prodrive had no financial involvement in the deal. Ford kept a stake in Aston Martin valued at £40 million (US$70 million).In order to demonstrate the V8 Vantage's durability across hazardous terrain and promote the car in China, the first east-west crossing of the Asian Highway was undertaken between June and August 2007. A pair of Britons drove 12,089 km (7,512 miles) from Tokyo to Istanbul before joining the European motorway network for another 3,259 km (2,025 miles) to London. The promotion was so successful Aston Martin opened dealerships in Shanghai and Beijing within three months.On 19 July 2007, the Newport Pagnell plant rolled out the last of nearly 13,000 cars made there since 1955, a Vanquish S. The Tickford Street facility was converted to Aston Martin's service and restoration department. UK production is now concentrated at Gaydon on the former RAF V-bomber airfield. In March 2008, Aston Martin announced a partnership with Magna Steyr to outsource manufacture of over 2,000 cars annually to Graz, Austria, reassuringly stating: "The continuing growth and success of Aston Martin is based upon Gaydon as the focal point and heart of the business, with the design and engineering of all Aston Martin products continuing to be carried out there."More dealers in Europe and the new pair in China brought the total to 120 in 28 countries.On 1 September 2008, Aston Martin announced the revival of the Lagonda marque, proposing a concept car to be shown in 2009 to coincide with the brand's 100th anniversary. The first production cars were slated for production in 2012.In December 2008, Aston Martin announced it would cut its workforce from 1,850 to 1,250 due to the ongoing economic recession.The first four-door Rapide grand tourers rolled out of the Magna...

Question: What was John Singer's profession?
investment banker