[londons_explore]

Traders wouldn't use redundancy etc. Whenever a packet with info arrives, they would trade on that info (eg. "$MSFT stock is about to go down, so buy before it drops!"). If there is packet loss, then some info is lost, and therefore some profitable trading opportunities are missed. But thats okay.

There are thousands of such opportunities each second - they can come from consumer 'order flow' - ie. information that someone would like to buy a stock tells you the price will slightly rise, so go buy ahead of them and sell after them in some remote location.

[sandworm101]

There is also a market for stocks that trade on different exchanges, resulting in fleeting differences in price between exchanges. Those who learn of price moves first can take advantage of such differences. In such cases, all you need to transmit is the current stock price. The local machine can then decide to buy or sell.