The Wall Street Journal prime rate is the most common measure of the prime rate, which is an index 3 percentage points above the federal funds rate set by the Federal Reserve. To get the rate, the Wall Street Journal surveys the nation’s 30 largest banks on their prime rates and publishes it in their print edition. Credit card issuers often peg their variable-rate cards’ interest rates to the prime rate, plus a margin that varies according to how risky the issuer views a consumer.