Responding to Knight Capital Group's $440 million loss from a trading glitch, Mike Lenhoff, chief strategist at Brewin Dolphin, told CNBC. "One has to look at this and say, look what is going on here, we don't want to be led by machines we are supposed to be led by rational decision making and machines are supposed to be the means to the end."
In this excerpt from "Closing Bell," Art Cashin of UBS talks with Bob Pisani, Bill Griffeth, and Maria Bartiromo, about today's apparent technological problem that disrupted the trading of almost 150 stocks this morning. He notes there were trading errors even before computers took over the process.