WASHINGTON (MarketWatch) - The Federal Reserve does not need to keep the $45 billion per-month pace of Treasury purchases under its Operation Twist effort when it converts the program to outright purchases, St. Louis Fed Bank President James Bullard said Monday. In a speech in Little Rock, Ark., and in an interview with The Wall Street Journal, Bullard said the central bank could reduce the size of the purchases and still have the same impact on the economy. "You could go down to $25 billion in outright purchases and probably get the same stimulative impact," he added. Under the Twist program, the Fed is offsetting the Treasury purchases with sales of shorter-term government securities so that the size of the Fed's balance sheet is held steady. The general consensus of Fed watchers is that the Fed will keep buying Treasurys and end the sale of the short-term-term paper at its meeting on Dec. 11 and 12. Bullard said the one-for-one replacement of Twist operations with purchases would be more dovish than current policy.