I can't load that page for some reason, and although I don't really like Krugman and certainly if it just comes from a blog with his opinion and vague handwavin

I can't load that page for some reason, and although I don't really like Krugman and certainly if it just comes from a blog with his opinion and vague handwaving in it I don't think it's worth much. But that surprises me that he would have changed his tune so quickly after being famously against HFT, e.g., https://www.nytimes.com/2009/08/03/opinion/03krugman.html https://www.nytimes.com/2009/08/03/opinion/03krugman.html > It’s hard to imagine a better illustration than high-frequency trading. The stock market is supposed to allocate capital to its most productive uses, for example by helping companies with good ideas raise money. But it’s hard to see how traders who place their orders one-thirtieth of a second faster than anyone else do anything to improve that social function. > What about Mr. Hall? The Times report suggests that he makes money mainly by outsmarting other investors, rather than by directing resources to where they’re needed. Again, it’s hard to see the social value of what he does. > And there’s a good case that such activities are actually harmful. For example, high-frequency trading probably degrades the stock market’s function, because it’s a kind of tax on investors who lack access to those superfast computers — which means that the money Goldman spends on those computers has a negative effect on national wealth.