I've never heard of any money managers treating comic books as a serious investment. Some collectors do, but professional money managers are way more risk-averse than that. Comic books are still very volatile. I've seen high-grade pedigree books lose two-thirds of their value over just a few years—I've seen it many, many times. Take the Mile High Green Lanterns, for example.
I know that Bill Hughes and a few other guys have tried to push comic books as serious investments, but most people recognize the volatility. Mega keys were pretty safe for a long time (and probably still are), but most books are very, very risky as long-term investments.