Learn about per diem interest, how it's calculated, its role in loans like mortgages, and why it's essential for borrowers to understand before closing a loan.

Editor's Note: APYs listed in this article are up-to-date as of the time of publication. They may fluctuate (up or down) as the Fed rate changes. CNBC Select will update as changes are made public.

Personal loans are a convenient way to cover a variety of expenses, like a wedding, vacation or surprise medical bill. Lenders typically disburse funds directly to your bank account and some will even ...