A former senior Lehman Brothers executive has become one of the new US heads of BlackRock's $1 trillion fixed-income business – as the firm's president promises he will have "less patience" with underperforming funds in the future.

The changes, announced yesterday in an internal memo from chief executive Larry Fink that has been seen by Financial News, are intended to pass the management of the fixed-income group "to the next generation", following a period of reorganisation aimed at improving performance.