Room to exploit arbitrage does not necessarily imply meaningful market inefficiencies. HFT only works because people with deep pockets can build huge fiber line

Room to exploit arbitrage does not necessarily imply meaningful market inefficiencies. HFT only works because people with deep pockets can build huge fiber lines directly connected to the stock exchange. It's a model where milliseconds matter in order to trade on differences of fractions of pennies. The market would operate just fine in the absence of HFT operators.