High Alpha Investor

"Alpha" in investing is synonymous with "smart." If you have lotsa Alpha, then you are "smarter than the market."

So a high Alpha investor is someone who beat the market while taking low risk—i.e. not a lot of leverage, not super volatile stocks or categories, etc. It's a new-ish term in "Modern Portfolio Theory" (which is a thing, apparently), that signifies that this fund manager or mutual fund is pretty awesome, and we can quantify that awesomeness with a number. Which we call alpha.