Investment firms value Excel so highly (and are so good at it, see this[1] amazing video that I saw on a previous HN thread of Martin Shkreli using Excel extremely effectively) that I'm sure they have internal training that is better than anything you can get outside.
Accountants pay very good money for Excel training, at least in Israel (I tried to compete with those courses by teaching Excel automation with Python, so I did some market research and customer development.)
Could you link to a specific moment where his Excel skills show? I have seen this video pop up from time to time and by clicking through the timeline all I ever see is him copying numbers from pdf's into Excel. Surely the whole "wizardry" aspect cannot just be the fact that he uses alt-tab and arrow keys instead of a mouse?
Accountants pay very good money for Excel training, at least in Israel (I tried to compete with those courses by teaching Excel automation with Python, so I did some market research and customer development.)
[1] https://www.reddit.com/r/videos/comments/4df5il/martin_shkre...