Fewer banks eased standards on loans to businesses in the third quarter, and lenders tightened standards on credit to European banks and their affiliates, according to a Federal Reserve survey.

Banks were slightly more likely to ease than tighten their standards on credit, “in contrast to more widespread reports of such easing in previous quarters,” the central bank said today in its quarterly survey of senior loan officers. Banks that raised their standards “cited a less favorable or more uncertain economic outlook as a reason for the tightening.”

Fed Chairman Ben S. Bernanke and his colleagues on the Federal Open Market Committee are struggling to boost an economy so weak that unemployment has been near 9 percent or higher for 31 consecutive months. In a press conference last week, Bernanke said the expansion is hampered by “still-tight credit conditions” for many households and small businesses and that “monetary policy has been blunted” by the dysfunctional mortgage market.