There are many areas of investing that work on a large scale - billion-dollar PE funds, public equity funds, multi-million-dollar real estate investment firms...
But how about some of the more niche and unusual areas of "investing" in the world where people still manage to make a killing? What's the most interesting/unusual/lucrative space you've encountered?
I think one my favorites would be the "quant" approach to sports betting - there's a British firm called "Starlizard" which does quant-based betting on Asian betting markets with different rules, and there's a great article by Bloomberg on how someone built an algorithm that can predict the outcome of horse races. Another two examples that I found interesting, but aren't quite as "niche" are litigation finance (with potentially significant asymmetric outcomes) and the interesting world of German closed-end funds that bought airplanes over the recent decade (and are now stuck with them - nobody wants big planes anymore...).
Would love to hear what some of you have seen and heard of!