It is curious as to why Fidelity is owning X shares. Is this on behalf of some sort of Fidelity mutual fund that invests in private companies? Or is some sort

It is curious as to why Fidelity is owning X shares. Is this on behalf of some sort of Fidelity mutual fund that invests in private companies? Or is some sort of alternative investment fund targeted at accredited investors only? Or do they invest the Fidelity customer cash balances in some sort of David Swenson style diversified portfolio?