It’s not easy to talk “insurance” with Gregory Case. Although as CEO of London-based Aon he oversees one of the world’s largest insurance brokerages and reinsurers, the 50-year-old prefers to discuss “risk” and “client solutions,” reflecting in part the 17 years he spent as an executive at management consulting firm McKinsey & Co. in Chicago. Since joining Aon in 2005, Case has quarterbacked the transformation of the insurer into what he calls a professional services firm, selling off its underwriting businesses and making two big acquisitions, paying $1.4 billion for reinsurer Benfield Group in 2008 and $4.9 billion for human resources specialist Hewitt Associates two years later.

Under Case, who has an undergraduate degree in finance from Kansas State University and an MBA from Harvard Business School,  Aon has seen its earnings per share more than double, from $1.69 in 2006 to $4.21 last year. Shares of the company have nearly tripled in value during his tenure, rising from roughly $22 when he started to a recent price of $62. Institutional Investor Editor Michael Peltz met with Case at Aon’s New York offices in March to talk about his plans for continuing to grow his company’s business in an increasingly complex and risky world, including the decision to move Aon’s headquarters last year from Chicago to London.

Institutional Investor:  What attracted you to Aon?

Case: I had watched the financial services industry for quite some time from where I was at McKinsey and had watched Aon because it was a Chicago....