The exchange was closed shortly after the beginning of World War I (July 31, 1914), but it partially re-opened on November 28 of that year in order to help the war effort by trading bonds, and completely reopened for stock trading in mid-December.
On September 16, 1920, a bomb exploded on Wall Street outside the NYSE building, killing 33 people and injuring more than 400. The perpetrators were never found. The NYSE building and some buildings nearby, such as the JP Morgan building, still have marks on their faades caused by the bombing.
The Black Thursday crash of the Exchange on October 24, 1929, and the sell-off panic which started on Black Tuesday, October 29, are often blamed for precipitating the Great Depression. In an effort to try to restore investor confidence, the Exchange unveiled a fifteen-point program aimed to upgrade protection for the investing public on October 31, 1938.
On October 1, 1934, the exchange was registered as a national securities exchange with the U.S. Securities and Exchange Commission, with a president and a thirty-three-member board. On February 18, 1971, the non-profit corporation was formed, and the number of board members was reduced to twenty-five.
One of Abbie Hoffman's well-known publicity stunts took place in 1967, when he led members of the Yippie movement to the Exchange's gallery. The provocateurs hurled fistfuls of dollars toward the trading floor below. Some traders booed, and some laughed and waved. Three months later the stock exchange enclosed the gallery with bulletproof glass. Hoffman wrote a decade later, "We didn't call the press; at that time we really had no notion of anything called a media event."
On October 19, 1987, the Dow Jones Industrial Average (DJIA) dropped 508 points, a 22.6% loss in a single day, the second-biggest one-day drop the exchange had experienced. Black Monday was followed by Terrible Tuesday, a day in which the Exchange's systems did not perform well and some people had difficulty completing their trades.
Subsequently, there was another major drop for the Dow on October 13, 1989the Mini-Crash of 1989. The crash was apparently caused by a reaction to a news story of a $6.75 billion leveraged buyout deal for UAL Corporation, the parent company of United Airlines, which broke down. When the UAL deal fell through, it helped trigger the collapse of the junk bond market causing the Dow to fall 190.58 points, or 6.91 percent.
Similarly, there was a panic in the financial world during the year of 1997; the Asian Financial Crisis. Like the fall of many foreign markets, the Dow suffered a 7.18% drop in value (554.26 points) on October 27, 1997, in what later became known as the 1997 Mini-Crash but from which the DJIA recovered quickly. This was the first time that the "circuit breaker" rule had operated.
On January 26, 2000, an altercation during filming of the music video for "Sleep Now in the Fire," which was directed by Michael Moore, caused the doors of the exchange to be closed and the band Rage Against the Machine to be escorted from the site by security after band members attempted to gain entry into the exchange.
In the aftermath of the September 11 attacks, the NYSE was closed for 4 trading sessions, resuming on Monday, September 17, one of the rare times the NYSE was closed for more than one session and only the third time since March 1933. On the first day, the NYSE suffered a 7.1% drop in value (684 points), after a week, it dropped by 14% (1370 points). An estimated of $1.4 trillion was lost within five days of trading.
On May 6, 2010, the Dow Jones Industrial Average posted its largest intraday percentage drop since the October 19, 1987, crash, with a 998-point loss later being called the 2010 Flash Crash (as the drop occurred in minutes before rebounding). The SEC and CFTC published a report on the event, although it did not come to a conclusion as to the cause. The regulators found no evidence that the fall was caused by erroneous ("fat finger") orders.
On October 29, 2012, the stock exchange was shut down for 2 days due to Hurricane Sandy. The last time the stock exchange was closed due to weather for a full two days was on March 12 and 13 in 1888.
On May 1, 2014, the stock exchange was fined $4.5 million by the Securities and Exchange Commission to settle charges it violated market rules.
On August 14, 2014, Berkshire Hathaway's A Class shares, the highest priced shares on the NYSE, hit $200,000 a share for the first time.
On July 8, 2015, technical issues affected the stock exchange, halting trading at 11:32 am ET. The NYSE reassured stock traders that the outage was "not a result of a cyber breach," and the Department of Homeland Security confirmed that there was "no sign of malicious activity." Trading eventually resumed at 3:10 pm ET the same day.