The Federal Reserve and Treasury are playing a dominant day-to-day role in overseeing Wall Street following this week’s rescue of Bear Stearns, raising the prospect that the central bank might be given more permanent authority over securities firms.

Bankers say the greater authority is a direct consequence of the Fed’s extraordinary decisions to extend a $30bn credit line to help JPMorgan Chase’s takeover of Bear and to lend emergency funds to securities houses for the first time in more than 70 years.