What is "sumzero"

SumZero is an investment website for professional investors (collectively referred to as the " buyside"), and buyside professionals are granted membership per an application, where they must be on the research team at a hedge fund, mutual fund, private equity fund, or investment banking proprietary trading desk. Its exclusivity is said to mirror that of Facebook at its outset, and though it currently has over 10,000 buyside members and over 40,000 'Basic' users, roughly 75% of buyside applicants for membership are rejected.