The Euros Want to Fix Computerized Trading in the Worst Way, and are Succeeding

HFT is under continued assault, both in the press and from regulators and legislators.  Europe is taking the lead on this, and Mifid II will impose some restrictions on HFT.  The Germans are particularly hot on restricting it, and are proposing other measures as well.

One goal of these regulations is to increase liquidity, and to improve the quality of liquidity.  Perversely, however, certain of the regulations intended to have these effects will do the exact opposite.

In particular, as I’ve argued since soon after the Flash Crash when many of these ideas were first proposed, things like minimum resting times for limit orders will reduce liquidity and make sudden reductions of liquidity more likely precisely when order flows become more toxic.  Limit orders are like options granted by the market maker, and extending the lifetime of the option increases its cost-particularly during times of high volatility and high order flow toxicity.  If you increase the costs that market makers, including those using HFT strategies to make markets,  incur to quote, they will quote wider, they will quote less, and their quotes will become particularly wide and particularly scarce during periods of elevated uncertainty.

In other words: there is no free lunch.  You raise the costs of market making, and liquidity costs go up.  Period.

Larry Tabb makes the point quite well:

So what will happen? If we mandate longer time in force periods, lower cancellation ratios, and higher market maker participation rates, liquidity providers will just widen their spreads to compensate them for the greater risk.

Won’t this force real investors to come in and bid? They may, however investors don’t quote on both sides of a market. They either buy or sell and not both. So many more quoting investors would be needed to make up for fewer market makers and HFT.

But, will HFTs actually leave? Market makers may leave but high-speed traders probably won’t; they will just change their stripes. Liquidity providers will flip to liquidity takers. Given a speed advantage, if it no longer serves a high-speed trader’s purpose to provide liquidity, they can just as easily take it. And since market makers and quoting investors are locked into providing liquidity for at least 500 milliseconds, HFTs will be the first to pick off every stale quote. And with a half second quoting mandate, there will be plenty of stale quotes to go around.

This last point is particularly powerful.  The regulations will penalize liquidity suppliers not just directly, but indirectly, by actively encouraging predatory/opportunistic algorithmic/HFT strategies that look for and pounce on quotes that are stale and not reflective of current information because of the restrictions on the time quotes must be enforced, and on cancellation and participation ratios.  (Note: these last restrictions are likely to create some rather complex time dependencies that can create some unanticipated sources of instability.  A trader’s current quoting behavior will depend on his past cancellation and participation rates, not just on current market conditions.  That adds a complex new feedback to an already complex process.)

The elimination of tiered pricing (e.g., differential pricing for quote makers and quote takers) will also tend to reduce liquidity.  Why don’t exchanges have the incentive and the information to get that right?  They are much better incentivized and informed than regulators.

So as Larry indicates, the regulations will reduce liquidity by raising the cost of quoting directly, and indirectly as well by encouraging predators to feast on those brave enough to quote:

So let’s combine points. Market makers will leave, spreads will widen, investors will post quotes, but HFTs instead of posting will take quotes. With investors’ quotes being frozen, HFTs will just pick off those investors. And once these investors learn this game they will stop posting, and then there will be little incentive for anyone to post quotes as the value of the limit order option grows just as the compensation to the option poster falls.

But won’t HFTs run afoul of HFT rules, you ask. Not really, since many of these rules focus on liquidity posting and not liquidity taking. If you take liquidity, there is no need to post or cancel, so cancellation rates decline to zero, and time-in force rules become immaterial.


Mifid II will also restrict those scary dark pools, in particular by banning crossing networks.  Which, as Tabb notes, will expose those seeking liquidity to predatory HFT, and other predatory strategies that raise execution costs.  For dark pools exist precisely to reduce the execution costs of those who are uninformed liquidity demanders. They swim in a (dark) pool because they don’t want to swim with the sharks in the open waters of the public markets.   Mifid will deprive them of that safe harbor, with the predictable result that Larry describes:

If all of this comes to pass, spreads will widen, depth will evaporate and there will be fewer places to hide as broker dark pools will face restriction. And the life of the buy-side trader, instead of becoming easier, will become much harder. And who suffers? The people who always suffer: the investors.

In other words, the Sorcerer’s Apprentices are at it again.  They claim to work magic that will make investors’ lives easier, but will in fact unleash forces that will wreak havoc.  And, no doubt, they will use the resulting havoc as the justification for yet more magical regulatory spells.

Not all HFT is good.  Not all algorithmic trading is efficiency enhancing.  It would be worthwhile to explore ways of curbing the inefficient forms of computerized trading without harming good forms.  There is justification for some regulation that can reduce the likelihood and impact of bad algos.   Mifid II is unlikely to have these effects.  Indeed, in my opinion-and in Larry Tabb’s too-it will likely have the exact opposite effect, and will disproportionately damage the beneficial forms of computerized trading and off-exchange trading.

Like the old joke says.  The Euros want to fix computerized trading in the worst way.  And they are succeeding.

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About Craig Pirrong 238 Articles

Affiliation: University of Houston

Dr Pirrong is Professor of Finance, and Energy Markets Director for the Global Energy Management Institute at the Bauer College of Business of the University of Houston. He was previously Watson Family Professor of Commodity and Financial Risk Management at Oklahoma State University, and a faculty member at the University of Michigan, the University of Chicago, and Washington University.

Professor Pirrong's research focuses on the organization of financial exchanges, derivatives clearing, competition between exchanges, commodity markets, derivatives market manipulation, the relation between market fundamentals and commodity price dynamics, and the implications of this relation for the pricing of commodity derivatives. He has published 30 articles in professional publications, is the author of three books, and has consulted widely, primarily on commodity and market manipulation-related issues.

He holds a Ph.D. in business economics from the University of Chicago.

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