Pension schemes are starting to rethink their hedge fund investments in the face of high costs and poor returns, putting at risk the heady pace of capital flows into an industry with nearly $3 trillion of assets.

Investors pulled more than $15 billion from hedge funds in the September quarter, industry data showed, ending six quarters of net inflows. Investments from large institutions such as pension funds contribute about 63 percent of hedge fund capital, according to industry tracker Preqin.

  Reuters