Prime Rate

What Does Prime Rate Mean?
The interest rate that commercial banks charge their most credit-worthy customers. Generally a bank's best customers consist of large corporations.

Investopedia explains Prime Rate
Default risk is the main determiner of the interest rate a bank will charge a borrower. Because a bank's best customers have little chance of defaulting, the bank can charge them a rate that is lower than the rate that would be charged to a customer who has a higher likelihood of defaulting on a loan.