Golden Boy is starting to become a HUGE threat to Arum and IMO has already surpassed King (in the talent he's promoting anyway), c'mon he has a pretty good stable of fighters, there's

The Golden Boy himself,
Oscar De La Hoya
Bernard Hopkins (if he decides to fight again)
Marco Antonio Barrera
Winky Wright
Shane Mosley
Kassim Ouma
Oscar Larios
Jhonny Gonzalez
Fernando Montiel
Jorge Barrios
Juan Lazcano
Kingsley Ikeke
Sultan Imbragimov
Marco Antonio Rubio

and good prospects like

Demitrius Hopkins
Ponce De Leon
Vincente Excobedo

give him some time and i believe he'll snatch away a couple other big names