Global shares fell on Tuesday and the U.S. dollar rose to a near one-week high as investors nervously eyed the spread of the Omicron coronavirus variant and awaited numerous central bank decisions due this week. Wall Street was lower and U.S. treasuries rose across the curve after U.S. producer prices increased by more than expected in November, another data point to support views that inflation could remain uncomfortably high for some time. "Mixed messages continue to reign as the year winds down," said Lindsey Bell, chief money and markets strategist at Ally Invest. "Hotter-than-anticipated PPI has upset the market, especially tech stocks. Yet, bond yields don"t seem to be worried about inflation ... as the 10-year sits 20 basis points below pre-Thanksgiving levels." US PPI US PPI The Federal Reserve is expected on Wednesday to announce that it is speeding up the end of its pandemic-era bond purchases and signal a turn to interest rate increases next year as a guard against surging inflation. Several central banks meet this week, starting on Tuesday when the Federal Reserve convenes for its two-day event, followed by the European Central Bank on Wednesday, the Bank of England on Thursday, and the Bank of Japan on Friday. While some investors are sitting on the sidelines, reluctant to take on new positions before year-end, others continue to be happy to "buy the dip," a strategy that has been successful throughout 2021"s strong rally, said Benjamin Bowler, equity analyst at Bank of America. "Markets can continue to run while they think there is solid ground beneath them, and only when they look down does gravity kick in," Bowler wrote in a note Tuesday. "(They) may convince themselves for some time that a less supportive Fed won"t derail the rally." Bowler said this market rally, which is largely fueled by the Fed"s stimulative bond-buying policy, is in real risk, especially because current inflation levels could limit what the Fed can do. By 2:40 p.m. EST (1940 GMT), MSCI"s gauge of stocks across the globe (.MIWD00000PUS) shed 0.87%, and the pan-European STOXX 600 index (.STOXX) lost 0.84%. The Dow Jones Industrial Average (.DJI) fell 97.14 points, or 0.27%, to 35,553.81, the S&P 500 (.SPX) lost 41.76 points, or 0.89%, to 4,627.21 and the Nasdaq Composite (.IXIC) dropped 225.83 points, or 1.47%, to 15,187.45. The fast-spreading Omicron variant also tamped down the mood on Wall Street after the S&P index (.SPX) last week hit an all-time closing high. Emerging market stocks lost 0.8%. MSCI"s broadest index of Asia-Pacific shares outside Japan (.MIAPJ0000PUS) closed 0.85% lower, after the Asian Development Bank (ADB) trimmed its growth forecast for developing Asia, reflecting risks brought on by the new virus variant. read more China"s CSI300 index (.CSI300) dropped 0.67%, after health authorities in Tianjin detected the country"s first Omicron case. read more The dollar index rose 0.191%, with the euro down 0.22% to $1.1258. The euro is seen as vulnerable given expectations that the Fed will tighten policy faster than the ECB. The yield on 10-year Treasury notes was 1.4411%, and the yield on the 30-year Treasury bond was 1.826%. U.S. crude settled at $70.73 per barrel, down 56 cents or 0.8%, and Brent closed down 69 cents at $73.70, down 0.9% on the day. Oil prices remain way off levels above $85 a barrel seen in mid-October before the variant was discovered. Reporting by Elizabeth Dilts Marshall in New York; Additional reporting by Tommy Wilkes in London; Editing by Will Dunham and Lisa Shumaker Our Standards: The Thomson Reuters Trust Principles.