On September 16, 1920, a bomb exploded outside the NYSE building on Wall Street in a terrorist attack, 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 in the facade 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, precipitated 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 not-for-profit corporation was formed, and the number of board members was reduced to twenty-five.

Following a 554.26 point drop in the Dow Jones Industrial Average (DJIA) on October 27, 1987, officials at the Exchange for the first time invoked the "circuit breaker" rule to stop trading. This was a very controversial move and prompted 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. In the afternoon, the 10 and 20% drops will halt trading for a shorter period of time, but a 30% drop will always close the exchange for the day. The rationale behind the trading halt was to give investors a chance to cool off and reevaluate their positions (see the October 27, 1997 mini-crash).

The first central location of the NYSE was a room rented for $200 a month at 40 Wall Street in 1817.

The NYSE was closed from September 11 until September 17, 2001 as a result of the September 11, 2001 terrorist attacks.

More space was clearly needed. So the Exchange invited eight of New York City's leading architects to join in a competition to design a grand new building. Their instructions: The trading floor was to have more space, more light, and more convenience for the transaction of business.

The Exchange chose the neoclassic design of architect George B. Post. Today, the Exchange building is considered one of Post's masterpieces and is a New York City and national landmark.

On May 1, 1901, The demolition of the old building at 10 Broad Street begins. The construction of the new building had a final cost of approximately $4 million

On April 22, 1903, The new Exchange building at 18 Broad Street opens to fanfare and festivity. It?s recognized from the first as an example of masterful architecture. The six massive Corinthian columns across its Broad Street facade impart a feeling of substance and stability and, to many, it seems the very embodiment of the nation's growth and prosperity.