大四学生的想法，希望论坛的前辈可以解答

feedbackplan

UIUC Msf  (Business) + Ma Econ  (Econ+Math)  + GMAT760 + letter from UIUC will be enough for you to get a PhD between top50~top100, e.g., Temple or UMAss.

feedbackplan

It is almost impossible to stay in original school because Ph.D.'s competition is extremely higher than MS. As a result, top MS (e.g., Harvard Stanford MIT) will end up to mid Ph.D. (e.g., UIUC), and you will be moved to next Tier if you are good enough (strong in econ is necessary).
  
But don't worry too much. You will get more info after your arrival at UIUC, and you can make your decision after then. Good luck!