Although Mr. Black started Apollo with his younger partners — Mr. Harris is 56 and Mr. Rowan 58 — he has been long been the face and voice of the firm.In building Apollo into a global financial powerhouse, Mr. Black has made himself and his co-founders immensely rich: His personal fortune is estimated at more than $8 billion, and he owns a massive private art collection — including a version of Edvard Munch’s “The Scream” — and is the chairman of the Museum of Modern Art.But when Apollo held its most recent earnings call in late October, there were already signs his dealings with …
