The main corporation is two words "Watch Tower" society of Pennsylvania. Don Adams took over for Milton Henschel in 2000 when the Governing Body cut all corporate ties, and when he died Robert Ciranko took over for him in 2014.
The next major corporation in line is the one word "Watchtower" society of New York. The JW's first black corporate president, Leon Weaver Jr., was president of this one up until recently. Not sure if he died or just stepped down (maybe something to do with their recent 80-years-old rule). He's now been replaced with Harold L. Corkern, a frequent JW Broadcasting speaker and former president of minor corporation "Kingdom Support Services".