About a-team Marketing Services
The knowledge platform for the financial technology industry
The knowledge platform for the financial technology industry

A-Team Insight Blogs

Talking Intelligent Trading with Andrew Delaney: The Flash Crash Blame Game

Subscribe to our newsletter

As you know, we don’t often wade in on macro market structure issues, preferring instead to stick to our proverbial knitting: trading infrastructure that uses high-performance technologies to introduce some smarts.

But the recent arrest of a culprit in the authorities’ long-running efforts to assign blame for the May 6, 2010, so-called Flash Crash – when the US equity and index future markets plummeted briefly then suddenly corrected themselves – raised our hackles somewhat. It seems strange to us that so momentous a market event as the Flash Crash could be caused not only by a single rogue trader, but one who lived in a two-bedroom semi just by Heathrow.

Furthermore, everything we’ve read about the incident seems to point to the possibility that nobody really knows what happened and that no single event was responsible.

With that in mind, we sat down last week with our friends Nick Idelson and Nicholas Hallam of TraderServe to talk about MiFID II. The two Nicks have been quite animated on the topic of non-live testing – that is to say, the testing of trading algorithms in real-world situations but not in the actual real world, where they can do damage if not properly checked. Non-live testing, it seems, is one of several (even many) of the requirements that would be ushered in under MiFID II under its current guise.

Nick & Nick have done a lot of work in this space in preparation for MiFID II. But on hearing the plight of Navinder Singh Sarao, the poor sod from Slough (or wherever it is) who’s taking the hit for the Flash Crash, they applied their testing ‘smarts’ to data from that fateful day five years ago.

Their paper on their findings is available for download here. I think it’s worth a read as it offers some genuine analysis of the way the trading day – and the days before and after – played out. Unlike much of the commentary I’ve read, it offers some genuinely plausible thoughts on what really happened, in short putting it down to a ‘perfect storm’ of perhaps four factors – of which Sarao’s spoofing / layering activities may be one.

The others, incidentally, included the large institutional sell order that was originally scapegoated by the SEC and CFTC; a drying up of high frequency trading liquidity as the market started to fall; and quote stuffing, a form of market manipulation across asset types, in this case equities to index futures. None, it seems, was enough to ‘cause’ the Flash Crash alone. But together they colluded to turn a downward blip into a rout.

The Nicks reckon the Flash Crash could’ve been avoided if MiFID II’s non-live testing requirements had been in place. MiFID II is coming, and evidence from the Flash Crash may convince regulators that it should include the non-live testing requirements, which currently suggest that execution venues will need to test members’ trading algos before allowing them to be used in live market conditions. That may be a tall order, not least because members don’t like handing over their algos to anyone.

TraderServe may have a solution to that issue in the form of the Algo Guard hosted deployment of its Algo Arena testing environment. When MiFID II kicks in, we may see a rush on facilities like this as high frequency traders seek to get their trading models approved so they can continue to do what they do.

Take a look at the TraderServe paper and judge for yourself.

Subscribe to our newsletter

Related content

WEBINAR

Upcoming Webinar: Navigating the Build vs Buy Dilemma: Cloud Strategies for Accelerating Quantitative Research

Date: 20 May 2026 Time: 10:00am ET / 3:00pm London / 4:00pm CET Duration: 50 minutes For many quantitative trading firms and asset managers, building a self-provisioned historical market data environment remains one of the most time-consuming and resource-intensive steps in establishing a new research capability. Sourcing data, normalising symbologies, handling corporate actions and maintaining...

BLOG

Industry Cautiously Backs EU Market Reform Ambitions, But Warns Execution Risks Loom Large

A panel at A-Team’s Group’s TradingTech Summit London 2026 offered a broadly supportive but clear-eyed assessment of the EU’s Savings and Investment Union (SIU) package, welcoming the shift toward a competitiveness agenda but warning the reforms risk falling short without bolder action on post-trade interoperability, data quality and regulatory simplification. The session, “The Evolution of...

EVENT

ExchangeTech Summit London

A-Team Group, organisers of the TradingTech Summits, are pleased to announce the inaugural ExchangeTech Summit London on May 14th 2026. This dedicated forum brings together operators of exchanges, alternative execution venues and digital asset platforms with the ecosystem of vendors driving the future of matching engines, surveillance and market access.

GUIDE

ESG Handbook 2021

A-Team Group’s ESG Handbook 2021 is a ‘must read’ for all capital markets participants, data vendors and solutions providers involved in Environmental, Social and Governance (ESG) investing and product development. It includes extensive coverage of all elements of ESG, from an initial definition and why ESG is important, to existing and emerging regulations, data challenges...