Algorithmic trading has increased in the past decade, and stock market liquidity has improved as well. By studying NYSE stocks over five years, researchers found that algorithmic trading and liquidity are positively related. They used the start of autoquoting on the NYSE as a way to measure the impact of algorithmic trading on liquidity. The switch to autoquoting led to quicker feedback for traders and algorithms, resulting in improved liquidity for large-cap stocks. Quoted and effective spreads narrowed, and adverse selection decreased, showing that algorithmic trading does indeed improve liquidity.