The mutual fund industry has been unable to persuade global financial regulators that labeling the largest financial companies  as systemically risky would impose additional costs on the companies, an industry official testified on Wednesday.

Subjecting mutual funds to bank-like regulation could hurt millions of Americans saving for retirement, Paul Stevens, president and CEO of the Investment Company Institute, told the Senate Banking Committee.

The international Financial Stability Board (FSB), an international body, and the U.S. Financial Stability Oversight Council (FSOC) have not been moved by the argument, he said.

He accused the FSB of being too secretive in its deliberations on whether to impose the Global-Systemically Important Financial Institution G-SIFI designation on the largest U.S.-based mutual funds.

Stevens said FSB isn’t required to tell a mutual fund it is being evaluated for G-SIFI designation and there are no ways for an investment fund or asset manager to challenge the label. He added the council also is not required to weigh the costs versus benefits of calling a mutual fund a G-SIFI.

There is no public information on what advice that Daniel Tarullo, the Federal Reserve Governor on the FSB, is giving that body.

The FSB “seems bent on producing recommendations to the FSOC calculated to expand the Federal Reserve’s own authority over U.S. asset management and capital markets,” he said.

In arguing against the need for more government oversight of his association’s members, Stevens called mutual funds among the most transparent and comprehensively regulated parts of the financial system.

He warned a G-SIFI or SIFI designation could mean a large mutual fund could be subject to the same 8 percent capital requirement imposted on banks.

In addition, he said SIFI-designated funds could be assessed fees by the Fed for regulatory costs and a charge to help pay for the resolution of a distressed financial institution deemed systemically important.