The trade body for the US investment industry has written a letter to the country's top three financial power brokers, urging them to bring their weight to bear over controversial global efforts to identify systemically important fund managers.

In a letter sent to US Treasury Secretary Jacob Lew, Federal Reserve chairwoman Janet Yellen and Securities and Exchange Commission chairman Mary Jo White late last week, the Investment Company Institute questioned the validity of recent regulatory efforts on designating fund managers as systemically important financial institutions.