The world faces a looming “retirement crisis” that requires a rethink of pensions and working patterns as medical breakthroughs boost longevity, BlackRock chief executive Larry Fink warned on Tuesday in his closely watched annual letter to chief executives and investors.

Fink, whose prior missives have helped boost interest in shareholder capitalism and climate change, cited UN projections that one in six people globally would be older than 65 by 2050, up from one in 11 in 2019, as he called for increasing global use of capital markets to help workers save for old age.

The BlackRock CEO also warned that the rise of defined contribution pension plans had combined with the growing strain on the social security government retirement programme to leave the US particularly unprepared for a huge increase in the retiree population.