[asfapifb]

> How is that physically possible? How can an exchange make sure that I, living in Europe, get to see Bob's order at the same time as an HFT set up in a building adjacent to the exchange?

Easy, trading cycles occur in (e.g.) ten second intervals synced to UTC atomic time. For instance results of trades propagated for five seconds, orders are accepted for five seconds and then are executed. This should allow enough time for reasonable latency and ensure that everyone has the most recent price on the exchange.

> At the same time I'm arguing that HFTs actually improve this situation (of market participants sharing the same information), instead of hinder it.

I decline to respond as I'm still undecided as to whether this is a good thing or not.

[runeks]

> Easy, trading cycles occur in (e.g.) ten second intervals synced to UTC atomic time. For instance results of trades propagated for five seconds, orders are accepted for five seconds and then are executed. This should allow enough time for reasonable latency and ensure that everyone has the most recent price on the exchange.

Right. But that would constitute a new type of trading -- similar to opening and closing auctions -- so it wouldn't be compatible with the current system.

But yes, it's definitely possible. The question is what the market prefers.