U.S. markets were mixed at the open amid political turmoil and worries over trade with China. Oil stocks fell as Saudi Arabia restored full production capacity ahead of schedule.

The Dow Jones Industrial Average opened up 70 points shortly after the bell or 0.28%. The Nasdaq Composite was marginally lower, falling 4.5 points or 0.06% and the S&P 500 was up 1.75 points or 0.06%.

House Speaker Nancy Pelosi’s decision to open a formal impeachment inquiry against President Trump weighed heavily on traders. Trump has admitted withholding military aid to Ukraine ahead of a July 25 phone call with his counterpart in Kiev but denied he asked Volodymyr Zelensky to investigate former Vice President Joe Biden, Trump’s leading rival so far in 2020. However, Rudy Giuliani, Trump’s personal lawyer has admitted asking the Ukrainians to investigate Biden and his son, Hunter, who held a board position with Ukraine’s natural gas company.

The White House has said it would release a transcript of Trump’s call with Zelensky, which the president has described as “perfect.”

Pelosi had been resisting calls for impeachment for months. She said she reversed her position Wednesday because the president’s actions “have seriously violated the constitution.”

The political turmoil comes as economic signals deteriorate globally, complicating decisions by central banks on whether to shore up growth.

Investors zeroed in on Trump’s comments at the United Nations when he said he would not accept a bad trade deal with China, dimming prospects for an agreement when high-level meetings take place early next month. He also accused China of abusing its membership in the World Trade Organization, using the WTO to carrying out an unfair trade agenda.

In London, the government remains hamstrung as the Oct. 31 Brexit deadline approaches. Prime Minister Boris Johnson lost his bid before the Supreme Court over Parliament’s suspension, giving opposition leaders a chance to head off a no-deal exit from the European Union. Labour leader Jeremy Corbyn pledged to block efforts to call an election until he is sure a no-deal Brexit would be impossible.

Global markets were lower. In Asia, Hong Kong’s Hang Seng index was off 1.28% while Japan’s Nikkei 225 fell 0.36% and China’s Shanghai Composite fell 1%. Australia’s S&P/ASX dipped 0.56%.

In early afternoon trading in Europe, London’s FTSE was 0.44% lower while the German DAX fell 0.98% and the French CAC was off 1.28%. The British pound was off 0.89% against the dollar while the euro fell 0.29% and the U.S. dollar index was up 0.38%.

Oil futures were lower. Crude and Brent oil were both off 2.29%, with crude falling to $56 a barrel and Brent falling to $60.70. Gold and silver also were lower.