On yahoo finance page it indicates HTA 52 week high $11.68. On the chart since first went public, I don't see it ever hit $11. Am I missing something????
F&C has one good answer; here's another: there's other historical price engines out there, and putting ALL your faith in Y! might not be the best idea :-). Got a brokerage account? Use their Research tab (or its equivalent) and see what turns up!
It happened on 11-15 at the opening when there was probably a trade imbalance. Someone must have put in a large market order at the opening and it shot up to $11.68 and back down within a minute.