> why would you ever publish it? Suppose you have a miraculous trading algorithm that you believe makes somewhat above-market returns with somewhat below-marke

> why would you ever publish it? Suppose you have a miraculous trading algorithm that you believe makes somewhat above-market returns with somewhat below-market risks, but you have only a small amount of capital you're happy to gamble with. Then what you can do by keeping your algorithm to yourself is: have investments that perform slightly better than most other people's. That's nice, for sure, but getting rich that way takes a long time unless you start out quite rich (or gamble a lot and get lucky, but that's also a way to get poor). On the other hand, what you get by publishing it might be a lucrative job offer at a hedge fund or investment bank, who hope you can use the skills you've just demonstrated to get them an extra 0.1% of return on their $10B pot. Now you have the opportunity to apply the same techniques to thousands of times more money than before, along with much more data and a server room full of hardware for backtesting and other smart people who will look at your clever ideas and maybe notice if there's a big mistake or omission. Of course most of the gains from your miraculous algorithm now go to the investors, and most of the rest probably go to other people with more seniority, but you are still likely to get rich faster and more reliably that way. I make no claim about the particular algorithm here or the person who published it. But the above seems to me like a pretty plausible reason why someone might prefer to publish, even if they have good reason to think their algorithm works.