BlackRock Inc.’s Larry Fink was among headliners at Saudi Arabia’s annual Davos-style investment confab in October. Days later, he popped up on a social media post from Abu Dhabi’s $1.5 trillion man, Sheikh Tahnoon bin Zayed Al Nahyan. The $11.5 trillion asset manager Fink runs recently received approval to set up its regional headquarters in Riyadh. It’s also teaming up with the Abu Dhabi royal.