Markets are said to be random by regulators and theoreticians, but none of the practitioners agree. They laugh at the thought that markets are random, all the while ignoring the fact that markets like the huge equity options complex are based on equations with probabilistic distributions at their heart.
With practitioner laughter ringing in your ears, you can go dig the data and what do you know, the time series are random. Now as most don’t know, there are many shapes of random and almost obviously market prices are bounded. While oil can go into negative values, it cannot go to a billion dollars a barrel. I wrote that with conviction then realised it wouldn’t take too much Weimar-style inflation for it to do just that, but even hyperinflation hits the buffers after a dozen or so zeros finally get printed on banknotes. It’s a good point, however, for how random market prices can and can’t be, but ultimately there are limits to the range of price randomness...