Given a choice between a regulator whose mission is to promote growth through investment, or an unfamiliar committee dominated by the Federal Reserve, the mutual-fund industry opted for the devil it knew.

The threat of regulation by the Financial Stability Oversight Council, an umbrella group charged with monitoring regulators' blind spots, encouraged fund companies to negotiate with the Securities and Exchange Commission on new rules for money-market mutual funds that were approved yesterday. The strongest provisions affect funds that hold about one-third of the industry's assets, while those catering to retail investors and holding U.S. government securities were exempted.

The Investment Company Institute, a lobbying group of fund sponsors that two years ago said it was "pleased" when the SEC failed to advance similar changes, saluted the SEC for striking "the proper balance" and "preserving the utility and value of these funds for investors." Money-fund sponsors such as BlackRock Inc. and Charles Schwab Corp.'s asset-management arm also embraced the rules, which exempted a large swath of the industry from the biggest changes.