A government agency is seeking to expand its authority to regulate risky trading overseas by affiliates of U.S. banks.

The proposal from the Commodity Futures Trading Commission comes just weeks after JPMorgan Chase & Co. announced it lost billions because of high-risk trades that took place at its London offices.

The CFTC commissioners voted this week without public debate to send the proposal out for public comment. It calls for extending the agency's oversight of derivatives to cover trading that takes place overseas.

Derivatives are financial instruments often used to hedge against future price fluctuations of an underlying commodity or security. But they have grown increasingly complex and risky. Losses stemming from a type of derivative known as credit-default swaps have been blamed for deepening the financial crisis.

The 2010 financial overhaul law gave the CFTC the authority to define which overseas transactions should be subject to oversight. The change would take effect in about a year.