Most exchanges that I have experience of have a minimum trade-to-quote ratio, i.e. at least a certain proportion of your quotes have to turn into trades, or you

Most exchanges that I have experience of have a minimum trade-to-quote ratio, i.e. at least a certain proportion of your quotes have to turn into trades, or you'll be warned and eventually kicked off the exchange. In any case, to the 'end user' (a regular stock investor like you or me) the continual jockeying for position among HFTs doesn't matter - all we notice is that we pay smaller spreads and get our orders filled more quickly. Sometimes the trading games spill out into the 'real world' with unpleasant consequences, but those instances appear (so far) to be rare. I think there needs to be tight regulation on HFTs to limit behaviour like quote stuffing, spoofing and other forms of gaming, but I don't agree with the argument that they are a net bad thing.