I was recently informed by the owner of an artificial intelligence fund that markets do not listen to economists any more. Rather than immediately dust off my CV and see what transferable skills I might have, I dug around for evidence of his claim and found there was something to it.

A fundamental shift in market structure towards rules-based, passive investing over the past decade means a lot of trading is no longer based on fundamentals. But just because some markets do not pay attention to economists, it does not mean economists should not pay attention to these markets. On the contrary — this shift in market structure could well be a trigger for the next global downturn. The US Federal Reserve is concerned enough that “Changing Market Structure and Implications for Monetary Policy” is the topic for this year’s economic symposium in Jackson Hole.

JPMorgan notes that only about 10 per cent of US equity investment is now done by traditional, discretionary traders. AI quant funds use powerful supercomputers to crunch huge amounts of data, unearth patterns and survey trading strategies across different markets in real time. They do not care why markets move, only that they do.