When you, or a hedge fund, or any other market participant, decide to sell or buy a security, the trade is submitted to a broker. That broker may submit the tra

When you, or a hedge fund, or any other market participant, decide to sell or buy a security, the trade is submitted to a broker. That broker may submit the trade to the floor, an ECN, or market maker, and so on. Only in very specific cases -- particularly an ECN to a specific exchange where it might have a spread with a regional exchange, is timing so critically important. But for 90% of those trades, it's a block limit order that sits on the order book until it's filled. For many trades this is irrelevant. For those where it does matter, it is the very last, smallest part of the system -- the execution engine -- where timing is everything. That is the part of the system where HFT engineers are building hyper-speed interconnects and optimizing every single instruction, but it is not relevant to the majority of the stack. Delays everywhere else in the system are largely meaningless -- yeah prices may have changed slightly, but unless you've mastered market timing (which no one has), it will generally even out and is irrelevant.