US Trading Circuit Breaker

I was searching for the web on the crashes in stock market, got names like:


Black Monday - 

• 28 October 1929, more investors decided to get out of the market, and the slide continued with a record loss in the Dow for the day of 38 points, or 13%.
• 19 October 1987, when stock markets around the world crashed, shedding a huge value in a very short time. The crash began in Hong Kong and spread west to Europe, hitting the United States after other markets had already declined by a significant margin. The Dow Jones Industrial Average (DJIA) dropped by 508 points to 1738.74 (22.61%).

Black Tuesday - 29 October 1929, Dow Jones Industrial Average fell 38 points to 260, a drop of 12.8%. The deluge of selling overwhelmed the ticker tape system that normally gave investors the current prices of their shares. Telephone lines and telegraphs were clogged and were unable to cope. This information vacuum only led to more fear and panic. The technology of the New Era, much celebrated by investors previously, now served to deepen their suffering.


Black Wednesday - 16 September 1992, when the British Conservative government was forced to withdraw the pound sterling from theEuropean Exchange Rate Mechanism (ERM) after they were unable to keep sterling above its agreed lower limit. George Soros, the most high profile of the currency market investors, made over US$1 billion profit by short selling sterling.


Black Thursday - 24 October 1929, when share prices on the New York Stock Exchange (NYSE) collapsed. Stock prices plummeted on that day, and continued to fall at an unprecedented rate for a full month

Black Friday -

• September 24, 1869 also known as the Fisk/Gould scandal, was a financial panic in the United States caused by two speculators’ efforts to corner the gold market on the New York Gold Exchange 
• The day following Thanksgiving Day in the United States, traditionally the beginning of the Christmas shopping season

Black Week - Beginning October 6 and lasting all week the Dow Jones Industrial Average closed lower for all 5 sessions. Volume levels were also record breaking. The Dow Jones industrial average fell over 1,874 points, or 18%, in its worst weekly decline ever on both a point and percentage basis. The S&P 500 fell more than 20%.^[7] The week also set 3 top ten NYSE Group Volume Records with October 8 at #5, October 9 at #10, and October 10 at #1.^[8]

I stumble on the following also, if there's a days whereby you are unable to trade, it could be the circuit breaker effect.

United States

There are three thresholds each of which represents different level of decline in terms of points in Dow Jones industrial average.

• In the event where threshold 1 is breached, the first halt is triggered. If that point is reached before 2 p.m., the market would shut down for an hour. If threshold 1 is breached between 2 p.m. and 2:30 p.m., the halt will last 30 minutes. No trading stops will take place if threshold 1 is breached after 2:30 p.m.
• If threshold 2 is breached before 1 p.m., the market would close for two hours. If such a decline took place between 1 p.m. and 2 p.m., there would be a one-hour pause. The market would close for the day if stocks sank to that level after 2 p.m.
• In the event where threshold 3 is breached, the market would close for the day, regardless of the time.

The thresholds are computed at the beginning of each quarter to establish a specific point value for the quarter.

For the second quarter of 2011, threshold 1 is 1200 points, threshold 2 is 2400 points, and threshold 3 is 3600 points.^[18]

The rules would halt trading on the major securities and futures exchanges in a coordinated cross-market halt if the circuit breaker is enacted.^[19

Resource : 

http://en.wikipedia.org/wiki/Stock_market_crash