A sudden spike in overnight lending rates this week is forcing the Federal Reserve to consider growing its holdings of Treasury securities for the first time in five years, putting a decision on the agenda for its meeting next month.

Fed Chairman Jerome Powell said Wednesday the central bank would be studying whether to increase its holdings, sometimes referred to as its balance sheet, carefully before approving any action at its Oct. 29-30 meeting.

“It is certainly possible that we will need to resume the organic growth of the balance sheet earlier than we thought,” he said at a news conference. “We’ll be looking at this carefully in coming days and taking it up at the next meeting.”

A decision to resume the growth of the Fed’s balance sheet wouldn’t mark the start of a new bond-buying program to stimulate economic growth by lowering long-term interest rates, like those the Fed began in several rounds after the 2008 financial crisis.

Instead, the Fed would begin buying small amounts of Treasury securities on a regular basis to prevent the amount of money in the banking system from declining. This marks a return to the normal precrisis practice of allowing the Fed’s balance sheet to grow in line with the broader economy.