[retube]

Markets are not as efficient as the textbooks would have you believe. Investors typically rely on a fairly small set of analysts for market news and views. It might take those guys a while to think about stuff, write a note etc. The deepseek crash last year lagged by several days as well.

[andai]

I'm out of the loop, but I thought there were sophisticated automated trading algorithms where people pay to install microwave antennas so they can have 1ms lower latency. And I thought those systems are hooked up to run sentiment analysis on the news. Maybe the news is late?

[retube]

High frequency is the domain of market makers. They are not taking positions in anything (well, only momentarily), they are just matching buyers with sellers. Actual investors move the market, and can be split into "fast money" and "real money". Fast money is basically hedge funds, holding periods typically hours - months depending on the strategy. Real money is the traditional investor base: asset managers, pension funds, sovereign wealth funds, insurers. These guys are much slower: e.g. the investment committee might meet once a quarter, and investment strategy (e.g "we're gonna get a bit longer UK real rates", or "dial US equity allocation down 5%") is often only updated annually.

[th0ma5]

That is generally only applicable to extremely momentary arbitrage opportunities. There's still a lot of automation though, but it's pretty boring. It's basically look at the news and make a recommendation to a fund manager or something, and various competing vendors of such, down to consumer products like that.