Blackstone made a variety of concessions, the majority of which have remained outside the public's view. : When Saudi Arabia pledged as much as $20 billion to help Blackstone Group LP build the world’s largest infrastructure fund, the kingdom wanted to be rewarded for its unprecedented commitment. One way Blackstone agreed to do just that: For every dollar that any other investor pays the asset manager to oversee its cash, Saudi Arabia gets to pay 15 cents less.