Using a novel dataset where all traders are identifiable, we examine trading in the shares of a major company on the London Stock Exchange before 1920. Our main finding is that bid-ask spreads increased in the presence of informed trades. However, we also find that spreads narrowed during...

We study liquidity provision by competitive high-frequency trading firms (HFTs) in a dynamic trading model with private information. Liquidity providers face adverse selection risk from trading with privately informed investors and from trading with other HFTs that engage in latency arbitrage...