vats of liquidity

What do you think of the big HFT study? It’s this big HFT study that CFTC chief economist Andrei Kirilenko conducted on S&P 500 e-mini futures at the CME, and it’s already inspired a metaphor from CFTC commissioner and all-purpose spinner of metaphors Bart Chilton:

Mr. Chilton said that the study would make it easier for regulators “to put forth regulations in a streamlined fashion. It’s a key step in the process and it should fuel-inject the regulatory effort going forward.”

Not his best effort, fine. Anyway, the study: I’m not sure I’ve earned the right to have an opinion, both because (1) that, generally, and (2) my model of high frequency traders as micro-mini-market-makers is a bit upended by the fact that the bulk of the HFTs in this study seem to be taking, rather than providing, liquidity.1 It’s possible that the e-mini market is not the best place to measure the overall effects of HFT, either for fundamental reasons (its use for hedging etc.) or more crassly because it lacks the liquidity rebates that drive a lot of HFT in other markets.

That said what I like about this study is that instead of measuring transaction costs in naive ways like “bid/ask spread,” it measures transaction costs in sensible ways like “in a series of zero-sum transactions, how much money do HFTs suck out in profits.” Though the measure of profitability is sort of kooky:

The profits calculated in Table 3 are the implied short-term profits: we calculate the marked-to-market profits of each trader on 1 minute frequencies2 and reset the inventory position of each trader to zero after each of these 1 minute intervals. Then, we sum up all the 1 minute interval profits to get a measure of daily profits. Therefore, we capture the short-term profits of traders and not gains and losses from longer-term holdings.

What this means is that if your model of market-making is “buy at 99.9, wait five minutes, and sell at 100.1,” then your profits might end up showing as 0.2 or -0.2 or zero or something else on that calculation.3 So regular old market making may look bad, while HFT market making – designed to move quickly – looks much better. And so you get this table: Read more »