Economic growth and consumer spending both risk being threatened by negative interest rates, the head of the world's largest asset management group has warned.
Larry Fink, chairman of BlackRock, said that the effect of negative rates - which are intended to encourage growth - was not being examined closely enough.
In his annual letter to shareholders he highlighted the uncertainty faced by investors "fuelled by slowing economic growth, technological disruption and social and geopolitical instability".
The chief executive, who has led the firm since its founding in 1988, said low rates were making it harder for savers to prepare for their retirement.
"There has been plenty of discussion about how the extended period of low interest rates has contributed to inflation in asset prices," he said.
"Not nearly enough attention has been paid to the toll these low rates - and now negative rates - are taking on the ability of investors to save and plan for the future.
"People need to invest more today to achieve their desired annual retirement income in the future."
A 35-year-old hoping to invest to adequately provide for their retirement faces having to save three times as much under a 2% interest rate than under a 5% interest rate to achieve the same outcome, Mr Fink said.
He added: "This reality has profound implications for economic growth: consumers saving for retirement need to reduce spending if they are going to reach their retirement income goals and retirees with lower incomes will need to cut consumption as well.
"A monetary policy intended to spark growth, then, in fact, risks reducing consumer spending."