Dealers say the lightspeed jump from 1.2750 to 1.2800 in EUR/USD a few moments ago was a screw-up by a dealer at a French bank. Apparently he was trying to key in a buy order at 1.2700 and put the wrong big number into the machine. He paid every offer in between.
I left the dealing room more than 10 years ago and still wake up with nightmares that I’ve done exactly that…