U.S. consumer sentiment slumped in December as Americans were rattled by on-going negotiations to avert the tax hikes and spending cuts set to come into effect in the new year, data showed on Friday. The Thomson Reuters/University of Michigan's final reading on the overall index on consumer sentiment tumbled to 72.9 from 82.7 in November, worse than forecasts for 74.7. It also came in under December's preliminary figure of 74.5. Talks to avoid the so-called fiscal cliff were thrown into disarray on Thursday evening when Republican lawmakers failed to back an effort by House of Representatives Speaker John Boehner ... (full story)