WASHINGTON (MarketWatch) -- The U.S. government ran a budget surplus of $3 billion in January, the Treasury Department reported on Tuesday, the first monthly surplus since September 2012. The surplus was driven by a 16% increase in revenues compared to January 2012, including from the expiration of a temporary payroll-tax cut at the end of 2012. For the first four months of fiscal 2013, the U.S. ran a deficit of $290 billion, $59 billion less than the same period in fiscal 2012. The government's fiscal year runs from October to September.