One of the potential disadvantages of recent innovations in trading technology is that the markets now move with lightning speed in both good times and bad. With trading in futures and securities regularly counted in milliseconds (i.e., one thousandth of a second) and even microseconds (i.e., one millionth of a second), market crashes and rallies now also can occur – and, indeed, have occurred – at breakneck speeds that make human reaction times seem tortoise-like. The same algorithmic trading technologies that have enabled the markets for futures, securities, and options to incorporate information into the prices of financial instruments more quickly than ever before also have resulted in occasional high-speed crashes and rallies whose causes have, at times, confounded market participants and experts.