"Deadline for Applications" ~Columbia Business School has two options~
There are two terms to apply Colombia business school, which depends on your needs to complete summer internship.
The application deadlines are like below;
January 2016 Entry:
Final application deadline : Oct 7, 2015
August 2016 Entry:
Early decision : Oct 7, 2015
Merit Fellowship Deadline: Jan 6, 2016
Final application deadline : Apr 13, 2016
Applicants who will enter January 2016 enroll second semester in summer, so they don't have to opportunity to involve with summer internships.
On the other hand, August Entrants can complete summer internships.
In addition, here is very important information about the differences between 'Early decision' and Regular Decision' for August applicants.