Eirin, being the Brain Of The Moon, would have the resources, temperament and long-term planning necessary for the job. She's taken incredible risks in starting and ending incidents. However, she might be the kind of person to intentionally crash the market to get rich off credit default swaps. Better to be with her than against her.
Miko has been a head of state, is an excellent negotiator, and would be able to satisfy the needs of her board of investors with her innate abilities. She is also a risk-taker, but they're less calculated and more based on innate feelings and more immediate concerns.
Keine would be the ultimate 'safe' person to manage a fund. Her way with history would allow her to spot trends and exploit them, or even manipulation history to make the market go her way. Her protective personality tells me she would rather invest in something proven to be profitable in the long term, rather than unreliable startups or fad investments.