Donald MacKenzie

About​ half of all buying and selling on many of the world’s crucial financial markets is now automated high-frequency trading. HFT is ultrafast. Whenever I speak to someone who might know and be prepared to tell me, I ask them just how fast that currently is: in other words, what’s the minimum time interval between the arrival of a ‘signal’ – a pattern of...

There’s a limit to how much you can learn while sitting at your desk reading the footnotes to balance sheets. Sometimes, a short seller has to become a field worker. Look at the website of Muddy Waters Research, for example, and notice the attention it pays to the physical world: precipitous, hairpin mountain roads down which huge volumes of timber would have to be hauled; satellite images of the possibly crumbling walls of a giant opencast mine; a solitary lorry idling outside what one might have expected to be a busy factory.

The​ VIX, or Volatility Index, is Wall Street’s fear gauge. I first started paying attention to it in the late 1990s. Back then, a level of around 20 seemed normal. If the index got to 30, that was an indication of serious market unease; over 40 signalled a crisis. The highest the VIX ever got was during the 1987 stockmarket crash, when it reached 150. In the 2008 global banking...