In November, Nasdaq unveiled a proposal for an “extended life” order type, which would encourage the posting of buy and sell orders on the Nasdaq Stock Market that last at least one second. In return for a commitment to keep the order live for a second or longer, the order would gain priority over others. Nasdaq’s proposed order type has been seen as an alternative to IEX’s best-known feature, the “speed bump,” a delay imposed to thwart certain predatory high-speed trading strategies.

https://www.wsj.com/articles/flash-boys-exchange-iex-criticizes-nasdaq-order-type-proposal-1488500411