Dec 17 (Reuters) - U.S.-based stock funds in the week ended Wednesday posted $5 billion in outflows, according to Lipper. U.S. taxable bond funds shed $559 million, the first outflow in six weeks, while money market funds were drawn down $52.2 billion, the biggest outflow since the week ended July 15, Lipper data showed on Thursday. (Reporting by Alden Bentley Editing by Chris Reese)