A board rate refers to an interest rate that the lender determines internally. How this rate is set, is something usually not revealed to the public. Unlike international lending or interest rates such as Libor, for example, if you try searching the term online and it returns no results or solely from one lender, chances it might be just a board rate.
With little transparency, and no telling how it will rise or fall in the future, consumers have begun avoiding them. So, some lenders have begun calling them by other names instead of board rates. Also, lenders usually include in their loan agreement the right to change their board rate at any point in time, giving the borrower only as little as 30 days’ notice.