The rise of external management fees paid by pension funds and other institutional investors are the largest part of total fund expenses, rising 55 percent over that last 15 years, according to a survey by Callan Associates.

The survey, which included 49 fund sponsors with a total of $219 billion in assets, found that the external fees accounted for 90 percent of total expenses. That's up from 83 percent in 1998, the first year Callan collected the data.

The survey, completed in April and May with public and private pension fund and foundations and endowments, showed that higher fees did not necessarily mean better returns. For average absolute returns, Callan reported, those in the bottom quarter of fees paid outperformed those in the top quarter when compared over one year and five years. For three- and 10-year periods, the reverse was true.