Treasury Secretary Janet Yellen conceded Tuesday that interest rates may have to rise to keep a lid on the burgeoning growth of the U.S. economy brought on in part by trillions in government stimulus spending. “It may be that interest rates will have to rise somewhat to make sure that our economy doesn’t overheat,” Yellen said during a economic seminar presented by The Atlantic. “Even though additional spending is relatively small to the size of the economy, it could cause some very modest increases in interest rates.” “But these are investments our economy needs to be competitive and productive,” she added. (full story)