The Square Mile has suffered another blow to its post-Brexit ambitions. Anthropic, the artificial intelligence powerhouse behind the Claude chatbot, has confirmed it will snub the London Stock Exchange in favour of a US listing. The decision, reported by Sky News, is a stark reminder that London’s efforts to attract high-growth tech companies are falling short.
For those of us who track capital flows, this is not a surprise. It is a pattern. Arm Holdings opted for New York. CRH moved its primary listing across the Atlantic. Now Anthropic, valued at over $60 billion, has joined the exodus. The company cited access to deeper capital markets and a more favourable regulatory environment for AI firms as key drivers. But let’s be honest. The real reason is that the US offers a deeper pool of institutional investors, higher valuations, and a culture that rewards risk-taking. London, for all its historical prestige, is increasingly seen as a backwater for tech.
The UK government has been desperate to position London as a global hub for AI. The Bletchley Park summit was a nice PR exercise. But words do not pay the bills. What companies want is a liquid market, supportive tax policies, and a regulatory framework that does not smother innovation before it can breathe. On this front, the US remains streets ahead.
Consider the valuation gap. A US-listed AI firm can command a price-to-earnings ratio that would make a City analyst blush. The same company on the London market would be lucky to get half that. This is not sentimentality. This is arithmetic. When you are raising billions to fund compute-intensive AI models, you go where the money is.
There is also the question of institutional knowledge. The US has a deep bench of analysts who understand tech. London’s investment community is still dominated by old money: miners, banks, and energy firms. They do not know how to price an AI start-up, and they are terrified of getting it wrong. So they offer conservative valuations, and the companies go elsewhere.
Anthropic’s snub is a symptom of a larger ailment. The UK’s regulatory approach to AI has been cautious, bordering on hostile. The EU’s AI Act is creating a compliance burden that will inevitably seep into UK rules. Meanwhile, the US is moving fast with lighter-touch regulation. The message to founders is clear: if you want to build at speed, do not list in Europe.
What does this mean for the UK economy? It is a leak of future tax revenues, high-skilled jobs, and the prestige that comes with hosting the world’s leading companies. The government can talk about ‘levelling up’ all it wants, but if the best companies are listing in New York, the benefits flow there too.
The Treasury will no doubt point to the UK’s strengths: its legal system, its time zone, its language. All true. But none of that compensates for the fact that the US market is simply larger and more attuned to tech. The London Stock Exchange’s attempt to reform listing rules has been too little, too late.
For investors, this is a wake-up call. UK pension funds and retail investors are being deprived of the chance to own a piece of the next big thing. They are left holding stakes in legacy industries while the AI revolution is funded by US capital. The result is a structural underperformance of the UK market relative to the S&P 500. This is not a short-term blip. It is a long-term divergence.
Anthropic’s decision is rational from a corporate perspective. But for London, it is a bitter pill. The city that once financed the Industrial Revolution is now watching the AI revolution sail past. Without a dramatic change in attitude and policy, this trend will continue. And the next Anthropic will again choose America.
The message from the market is clear: adapt or be left behind. But so far, the only adaptation has been a slow, painful decline.
