The U.S. Supreme Court appeared wary Monday of second-guessing the fees that mutual funds pay to the investment advisers who run them. The Court heard oral arguments in Jones v. Harris Associates, a closely watched case that could have major impact on the fee structure in the nation’s $10 trillion mutual fund industry.

At issue is whether and when, under the Investment Company Act of 1970, shareholders in mutual funds can challenge what they view as excessive fees paid to investment advisers by the funds. Business groups urged the Court to stick with a 27-year-old standard that gives substantial deference to the funds, but investor groups said runaway fees have resulted from the overly close relationship between fund boards of directors and investment advisers.