In December, Richards will take over as chief executive of Fidelity International which operates outside the U.S. and has some $309 billion in assets under management. Richards, a nuclear physicist by training, is going to Fidelity from one of its rivals, fund manager M&G Investments, which she led for two years. During her tenure at M&G, its parent Prudential had merged the investment management business with its European life insurance arm. Richards, one of the better-known figures in Europe’s asset management industry, remained head of M&G and became deputy chief of the combined M&G Prudential last year.