We compare the optimal trading strategy of an informed speculator when he can trade ahead of incoming news (is "fast"), versus when he cannot (is "slow"). We find that speed matters: the fast speculator's trades account for a larger fraction of trading volume, and are more correlated with...

Short lived arbitrage opportunities arise when prices adjust with a lag to new information. They are toxic because they expose dealers to the risk of trading at stale quotes. Hence, theory implies that more frequent toxic arbitrage opportunities and a faster arbitrageurs' response to these...