Speaker Nancy Pelosi visits TaipeiCaterpillar falls after missing sales estimatesUber surges after reporting positive cash flowIndexes: S&P 500 -0.13%, Nasdaq +0.29%, Dow -0.70%Aug 2 (Reuters) – Wall Street was mixed in choppy trading on Tuesday, with geopolitical tensions flaring after U.S. House of Representatives Speaker Nancy Pelosi visited Taiwan.Pelosi said her trip demonstrated American solidarity with the Chinese-claimed self-ruled island, but China condemned this first such visit in 25 years as a threat to peace and stability. read more Shares of chipmakers heavily exposed to China were trading mostly higher, rebounding after early declines.Advanced Micro Devices (AMD.O) rallied about 3% ahead of its quarterly report after the bell.Register now for FREE unlimited access to Reuters.comRegisterIndustrial bellwether Caterpillar (CAT.N) dropped almost 5% after warning of a bigger drop in demand for its excavators in property crisis-hit China, piling more pain on the industrial bellwether grappling with supply-chain disruptions.Financial markets have also been roiled by the Ukraine war, soaring inflation and tightening financial conditions.U.S. job openings in June fell by the most in just over two years, as demand for workers eased in the retail and wholesale trade industries. Overall the labor market remained tight. read more After the Fed raised interest rates by 75 basis points in July, investors have speculated about whether the central bank’s largest hikes are behind it.”The market has to get really comfortable that they have fully baked in all the Fed’s rate hikes, and I think that remains an open question,” said Rob Haworth, senior investment strategist at U.S. Bank Wealth Management in Seattle. “The challenges and supply constraints aren’t necessarily done. They aren’t done and gone yet.”Shares of U.S. defense companies Raytheon Technologies Corp (RTX.N), Lockheed Martin Corp (LMT.N), Northrop Grumman Corp (NOC.N) and L3Harris Technologies Inc (LHX.N) rose between 1% and 3%. The United States is Taiwan’s main supporter and arms supplier. read more In afternoon trading, the S&P 500 was down 0.13% at 4,113.41 points.The Nasdaq gained 0.29% to 12,404.69 points, while the Dow Jones Industrial Average was down 0.70% at 32,569.39 points.The CBOE volatility index (.VIX), also known as Wall Street’s fear gauge, eased from the day’s high of 24.68 points. The Philadelphia SE semiconductor index (.SOX) bounced back from losses to rally about 0.6%.A largely upbeat second-quarter reporting season has supported markets recently, with the benchmark S&P 500 index (.SPX)up about 12% from lows hit in mid-June.Uber Technologies Inc (UBER.N) jumped 18% after the ride-hailing firm reported positive quarterly cash flow for the first time ever and forecast upbeat third-quarter operating profit. read more Tesla Inc (TSLA.O)gained 2.7% after Citigroup hiked its price target on the electric car maker’s stock.Pinterest Inc (PINS.N) surged almost 13% after activist investor Elliott Investment Management became the largest shareholder of the digital pin-board firm. read more Across the U.S. stock market (.AD.US), advancing stocks outnumbered falling ones by a 1.0-to-one ratio.The S&P 500 posted 2 new highs and 30 new lows; the Nasdaq recorded 37 new highs and 61 new lows.Register now for FREE unlimited access to Reuters.comRegisterReporting by Aniruddha Ghosh and Devik Jain in Bengaluru; Editing by Anil D’Silva, Arun Koyyur and David GregorioOur Standards: The Thomson Reuters Trust Principles.