A trader at the New York Stock Exchange reacts on Oct. 19, 1987, when the Dow Jones industrial average plunged more than 22 percent — the biggest single-day drop in history.
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A trading hall sits empty in a securities firm in Haikou, China, Monday. Trading on the Shanghai and Shenzhen stock markets was ended before 2 p.m. Monday after shares tumbled 7 percent.
Zhao Yingquan/Xinhua /Landov
Iranian stockbrokers monitor share prices at the Tehran Stock Exchange in April. The historical Iran nuclear deal could open the country's market up to international investors.
An investor looks through stock information at a trading hall in Haikou, the capital of Hainan province in southern China. Since mid-June, the main Shanghai stock index has lost 30 percent.