—but I am looking at the remaining interest left, which is about $4000 total. That comes out to be at 1.31% apr…So where can I find a 1.5% or higher return that is guaranteed over the next 3 years?—

You made a math mistake in there somewhere. If your loan interest rate is 2.75%, there is no scenario where you’d be better off investing at 1.5% versus paying the loan down further.