Diekmann began his career with Allianz in 1988 after becoming frustrated with his own business, a publishing house that focused on travel guides.[4] During his career, he later worked in Australia and the United States, where he successfully revamped the Fireman's Fund Insurance Company, the Allianz subsidiary there.[5] In 1996, he moved to Singapore to run Allianz's Asia-Pacific business front.[6]
As CEO, Diekmann steered Allianz through a difficult period at the start of the century, moving it from a low point in profitability to a bumper year in 2013 with an operating profit of €10.1 billion.[7] Under his leadership, the insurer also converted its legal form, then Aktiengesellschaft, or German joint-stock company, to Societas Europaea (SE) in 2006.[8] By 2014, Allianz had grown to become the world’s second-biggest investor after BlackRock.[9] That same year, Diekmann weathered a hailstorm of criticism about the sagging performance at the firm’s asset manager, Pimco.[10]
Diekmann's total compensation from 2010 was around one hundred and five million Euros.[11]
In late 2014, it was announced that Diekmann, would step down the following year after he turned 60, which is traditionally the age limit for board members at Allianz.[12] At the time, investors widely expected him to stay in his role for a further one to two years.[13]
