U.S. stocks slipped in light trading, with the Standard & Poor's 500 Index posting back-to-back declines for the first time this month, as investors considered the capacity of central banks to boost global growth.

U.S. equities retreated with shares in Asia and Europe after the Bank of Japan refrained from adding more stimulus. Central banks around the world have indicated a willingness to continue measures to support economic growth and stabilize markets, helping stocks rebound in the past month. The Federal Reserve kicked off a two-day policy meeting today, with investors tempering their trading before the outcome Wednesday afternoon.

Fed officials have stressed that the pace of rate increases will be gradual and data-dependent. A report showed retail sales dropped in February and the prior month's gain was revised to a decline, calling into question the narrative that bigger gains in consumer spending would propel economic growth at the start of 2016. Separate data showed wholesale prices fell last month, held down by lower fuel costs that have kept inflation languishing below the Fed's goal.

Another measure showed confidence among homebuilders held in March at a nine-month low as sales prospects waned, while other data indicated inventories at warehouses, stores and showrooms are not being drawn down amid tepid underlying demand.