Four?
It's six!
> Trump Taj Mahal Associates, Atlantic City casino — 1991
> Trump Castle Hotel & Casino, Atlantic City casino — 1992
> Trump Plaza Associates, Atlantic City casino — 1992
> Plaza Operating Partners, Manhattan hotel — 1992
> Trump Casino Holdings, Atlantic City casinos — 2004
> Trump Entertainment Resorts, Atlantic City casinos — 2009
The five casinos were filed in New Jersey, the "partners" were filed in New York.