Manny Roman is taking over as chief executive of the world's biggest bond fund manager at a time when bond funds are under acute strain due to central bank policies and low liquidity.

The head of fixed income at a rival manager raised his eyebrows at Roman's decision to join Pimco, saying it was "the worst time to take a position of high responsibility" at the $1.5 trillion bond giant, part of Allianz, adding "it will be stressful". This is in part because central banks have bought so many of the world's bonds, reducing liquidity and squeezing investment options.