There is no general answer to who should hold the copyright to your thesis. According to the "Specifications for Thesis Preparation" (in part):
For information about who should hold the copyright on your thesis, please consult your department headquarters or thesis advisor. Please verify your copyright information BEFORE your thesis is due!
If the thesis is copyrighted to you, you must give the Institute permission to distribute it, and should use the "vi" documentstyle in your main thesis file. Specifically, in the first line that says something like this:
add the vi option like so:
Again, check with your department or thesis advisor as early as possible to avoid major problems!