In this interview, he says,

But when it comes to something like investment banking versus commercial banking, the experience in a country like Canada would indicate that good, strong regulation that focuses less on the legal form of the institution and more on the functions that they’re carrying out is probably the right approach to take.

Canada does not separate investment banking from commercial banking. Concerning this interview, Tyler Cowen writes,

I do not agree with Obama on all points but he understands economic policy better than do most professional economists