Thanks for replying. I like your time averaged argument, that seems to be a good explanation of why it is useful, both to the trading entity and to the market, to be able to change orders quickly.
I think my final question about the balance between total costs and benefits is motivated by the fact that discussion about HFT and similar price-based trading always makes it sound like a lot of effort is being invested in the competition to find profit-making trades, and my wondering whether all that effort could be more productively used elsewhere.
I understand the market motivation behind doing it, which I think yours and others' explanations justify well, however, as I mentioned previously, I remain unconvinced by the allocative efficiency of markets in all situations, and these 'arms race' situations seem like good candidates for market failure (to stress, I mean failure only in terms of the societally-efficient allocation of resources, I don't doubt the local efficiency).
Your note about HFT profits obviously goes some way to addressing this by suggesting that the level of resource allocation isn't that high - I have to confess I didn't realise the profits were quite so low. I do, however, think that revenue is the more important figure, because that will capture the productive effort that we, as a society, are investing in this activity, which we can then usefully compare to the liquidity benefit we get from it.
In case you are interested, I think I have been spurred down this line of thinking by having recently read 'The Collapse of Complex Societies', by Joseph A Tainter, which I can heartily recommend if you haven't already read it. My argument is really his, just applied to the frontier of our times - finance.
And as a personal aside, if you don't mind my asking, you seem to have a good understanding of the realities of this situation, were or are you involved professionally?
I think my final question about the balance between total costs and benefits is motivated by the fact that discussion about HFT and similar price-based trading always makes it sound like a lot of effort is being invested in the competition to find profit-making trades, and my wondering whether all that effort could be more productively used elsewhere.
I understand the market motivation behind doing it, which I think yours and others' explanations justify well, however, as I mentioned previously, I remain unconvinced by the allocative efficiency of markets in all situations, and these 'arms race' situations seem like good candidates for market failure (to stress, I mean failure only in terms of the societally-efficient allocation of resources, I don't doubt the local efficiency).
Your note about HFT profits obviously goes some way to addressing this by suggesting that the level of resource allocation isn't that high - I have to confess I didn't realise the profits were quite so low. I do, however, think that revenue is the more important figure, because that will capture the productive effort that we, as a society, are investing in this activity, which we can then usefully compare to the liquidity benefit we get from it.
In case you are interested, I think I have been spurred down this line of thinking by having recently read 'The Collapse of Complex Societies', by Joseph A Tainter, which I can heartily recommend if you haven't already read it. My argument is really his, just applied to the frontier of our times - finance.
And as a personal aside, if you don't mind my asking, you seem to have a good understanding of the realities of this situation, were or are you involved professionally?