The Knight Capital meltdown was an accident. So we are told– based on careful examination of the trading patterns and educated guesses, the culprit appears to be some testing code mistakenly released into the wild where it started conducting trades with real money on a real exchange, instead of the simulated environment used to verify the trading algorithms. There is no post-mortem released, at least not for public consumption– perhaps the SEC has received one under a confidentiality agreement. (That is a shame. The post-mortem would be required reading for software engineers, as another case study of a catastrophic bug missed before release, right up there with AT&T outage of 1990, Intel Pentium floating point unit and other epic failures.) Recalling the admonition, variously attributed to Robert Heinlein, that one should not attribute to malice what can be explained by incompetence, let us grant that there was no foul played involved. No rogue trader upset by his/her latest bonus, no corrupt insider bribed by a competitor to throw a wrench into the gears, no Stuxnet-style targeted malware poisoning the trading algorithms. The episode still provides a glimpse into the scale of disruption possible from a deliberate attack on markets, carried out by a skilled adversary in control of a high-frequency trading system.
Concerns have been raised in the past about the systemic risks from high-frequency trading, including the increased volatility and possibility for short-lived but significant pricing anomalies such as the Flash Crash of May 2010. (That incident turned out to be an unrelated problem, triggered by a large sell order from Kansas of all places.) Most of these critiques focus on accidental bugs, instead of deliberate attacks against the system. While Knight Capital proves the timeliness of the random-failure model, it paints an even more bleak picture in terms of the likely robustness of the system in adversarial settings. In other words, inability of quality assurance process to catch even “good-intentioned” bugs does not bode well for its ability to stop malicious tampering that is deliberately designed to evade detection.
One objection is that the errant trading did not result in destruction of wealth as much as it facilitated a coordinated and rapid transfer. Specifically, funds migrated away from the NJ firm and towards a multitude of other HFT shops on the winning side of the botched trades. It is a zero-sum game, this argument goes, and markets were efficient at punishing Knight Capital for its mistake, moving capital to other participants where it will be put to less foolish use. While the zero-sum property may have been (approximately) maintained this time around, it is not clear how that assurance can scale as the size of the disruption increases. The pattern of trading can just as easily cause prices of underlying assets to decline, generating losses for unrelated third-parties holding on to the same positions. The flash-crash of May 2010 was precisely such an incident that triggered a precipitous but short-lived decline in the market. The second problem is that drastic fluctuations can cause the proverbial “loss of investor confidence” among non-institutional investors, as well as disappearing liquidity as automated systems exit the market when reality parts ways from their models.
The likely suspect both in possession of resources to execute such an attack and motives to benefit from the ensuing chaos are nation states. Non-state actors such as terrorist groups may have motive, but probably lack the sophistication and access to markets with signficant capital. (Still the idea of villains initiating market mayhem while placing bets on the result has been a timeless plot device for B-grade action movies.) As for commercial entities, it is very risky for any legitimate company to actively tamper with a competing trading platform or ECN in order to reap profits. Getting caught has career limiting consequences for all involved. (On the other hand, theft of competitors’ trading model with the purpose of either front-running them or better yet trading against them is well within the realm of unethical possibilities, as in the Goldman Sachs programmer caught stealing source code in 2009.)
State sponsored computer warfare has received a lot of attention and FUD recently, mostly focused on the vulnerability of critical infrastructure such as the power grid or communication systems. Markets are not “critical infrastructure” in the sense that temporary disruption is not as life-threatening as widespread blackouts or toxic chemical release from industrial systems. On the other hand, it may have a very disproportionate effect on the economic well-being of the US. It is no secret that past waves of APT targets included financial institutions. But the geopolitical context driving such attacks and their objectives are complex. Stealing trade secrets or source code from companies headquartered in a different country provides an economical advantage to the country initiating the theft, as well as any domestic competitors who become the recipients of said ill-gotten goods. It is not surprising that some nations have embraced the practice as an integral component of foreign policy. But given the tight coupling between national economies (“when the US sneezes, rest of the world catches a cold”) an action causing wholesale market disruption would have repercussions for the aggressor as well. This poses a particular challenge for China, long suspected as main perpetrator of attacks against US networks. It is one of the largest holders of US Treasuries, and its growth engine remains dependent on US companies that outsource manufacturing operations. Then there is the collateral damage to sovereign wealth funds associated with other nations invested in the same market, making it difficult to separate allies from foes in terms of harm inflicted by an indiscriminate attack against trading infrastructure.