World shares are mixed as a US government shutdown adds to uncertainty

U.S. futures sank and world shares were mixed after a U.S. government shutdown began on Wednesday.

The future for the S&P 500 dropped 0.8%, while that for the Dow Jones Industrial Average gave up 0.7%. On Tuesday, the S&P 500 rose 0.4% and the Dow gained 0.2%, to set an all-time high. The Nasdaq composite ticked 0.3% higher to 22,660.01.