Wall Street falls on rising US-China tensions; Uber gains post Q2 results

Speaker Nancy Pelosi expected in Taipei later today; Caterpillar falls after missing sales estimates; Uber gains after reporting positive cash flow

Wall Street's major indexes fell on Tuesday on concerns over rising U.S.-China tensions ahead of the arrival of U.S. House of Representatives Speaker Nancy Pelosi in Taiwan, with losses in industrial bellwether Caterpillar adding to the slide.

Shares of chipmakers with a large exposure to China fell, while Caterpillar slid 3.6% as slowing construction activity in the world's second largest economy and a halt in Russia operations added to its supply-chain woes.

"Chip stocks are really exposed to Asia. Some of them have 70% of their sales, especially chip equipment companies, in that region so it's a big deal for them," said