Banks and asset managers running money-market funds may be forced by the European Union to raise capital buffers and hoard easy-to-sell assets as part of a regulatory push to tame the $4.7 trillion global industry.

Michel Barnier, the EU's financial services chief, said such buffers would have dealt with most difficulties suffered by fixed share-price funds in the wake of the 2008 financial crisis, as he rejected calls for an outright ban from German Finance Minister Wolfgang Schaeuble, his French counterpart Pierre Moscovici and a group of EU regulators.

Money market funds "are not always stable, and in a period of tension they can threaten the financial system, including the banks," Barnier told reporters in Brussels. He said "a formal and brutal ban" of fixed share-price funds sought by some regulators was unnecessary and would hamper investors.