WASHINGTON (MarketWatch) -- The U.S. posted a record $48.3 billion budget surplus in December, as year-to-date receipts and outlays also hit record highs, the Treasury Department reported Friday. The monthly surplus is a bit higher than the $47 billion estimated earlier this week by the Congressional Budget Office. The December figure is 15% above the year-ago surplus of $42 billion. Year to date, the U.S. is running a budget deficit of $105.5 billion.