-nog down 58%
Exchange Circuit Breakers
Stock exchanges can also take measures to ease panic selling by invoking Rule 48 and halting trading when markets have severe downside movements. Under 2012 rules, market-wide circuit breakers (or 'curbs'
Circuit breakers can also be imposed on single stocks as opposed to the whole market. Under current rules, a trading halt on an individual security is placed into effect if there is a 10% change in value of a security that is a member of the S&P 500 Index, Russell 1000 Index or QQQ ETF within a 5-minute time frame, 30% change in value of a security whose price is equal or greater than $1 per share, and 50% change in value of a security whose price is less than $1 per share.