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. More on stocks: https://www.amazon.com/gp/search?ie=UTF8&tag=tra0c7-20&linkCode=ur2&linkId=76d788a3703b8fff187a2f806c15b98b&camp=1789&creative=9325&index=books&keywords=stocks
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 façades 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 real dollars mixed with fake dollars toward the trading floor below. Some traders booed, and some collected the apparent bounty. The press was quick to respond and, by evening, the event had been reported around the world. (The stock exchange later spent $20,000 to enclose 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, prompting officials at the exchange to invoke for the first time the "circuit breaker" rule to halt all trading. This was a very controversial move and led to a quick change in the rule; trading now halts for an hour, two hours, or the rest of the day when the DJIA drops 10, 20, or 30 percent, respectively. The rationale behind the trading halt was to give investors a chance to cool off and reevaluate their positions. 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, 1989; the 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.
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. Trading on the exchange floor, however, continued uninterrupted.
In the aftermath of the September 11, 2001 terrorist attacks, the NYSE was closed for 4 trading sessions, one of the longest times the NYSE was closed for more than one session; only the third time since March 1933.
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.