High frequency trading is the practice of executing multiple transactions for securities followed by extremely short holding periods. Such market practices often require highly sophisticated computing and communications technologies. Many market observers have commented that high frequency trading (HFT) is unfair to small investors who lack the high-priced equipment and technology to compete with much larger traders. Many of these observers have proposed curbs on HFT activity, including having exchanges and other markets replace continuous trading with batch trading or call markets. Why would batch trading (call markets) reduce the level of HFT?