Your statement arrives and the interest rate is different. You paid on time. You did nothing. So what happened? Most likely, your card has a variable APR. APR means annual percentage rate, the yearly cost of borrowing on your card. Let me walk through how it moves, step by step.
What a variable APR actually is
A variable APR is a rate that can change over time because it is tied to an index. An index is a published benchmark rate. The Consumer Financial Protection Bureau (CFPB) gives the prime rate, as published in the Wall Street Journal, as one example. When the index moves, your card's rate moves with it. Most credit cards carry variable rates.
A fixed APR does not follow an index. But fixed does not mean frozen. The CFPB says an issuer can still change a fixed rate. In most cases it must tell you first, and it can generally apply the higher rate only to purchases made after the notice.
One more piece of vocabulary. Your rate is usually the index plus a margin. The margin is a set number of percentage points the issuer adds. The sources I reviewed do not explain how any one issuer picks its margin, so your agreement is the place to look.
Why the index moves
The prime rate closely follows the federal funds rate. That is the rate set by the Federal Open Market Committee, the Federal Reserve group that guides monetary policy. When the Fed raises or lowers its target, the prime rate typically follows. Variable card rates then usually follow the prime rate.
That chain is public. Fed announcements are widely reported, so the direction of a change is often easy to guess even when the timing is not. I cannot give you today's prime rate or card rates here. Check your own statement and the Fed's published data for current numbers.
The index is not the only reason a rate can rise. One issuer's education page notes that a drop in credit scores or a penalty can also push a variable APR up. Those changes are tied to your account, not to the Fed.
What notice you must receive
Federal rules generally require 45 days of advance written notice before an issuer raises the rate on new purchases. That gives you time to pay down a balance or change how you use the card.
There are other timing rules to know:
- Issuers generally cannot raise the rate on new transactions during the first year of the account.
- Purchases made more than 14 days after the advance notice are treated as new transactions at the higher rate.
- A rise caused by the index going up does not require a notice to you, because the agreement already said the rate would move with the index.
Even then, the bank must send written notice of significant term changes. If you agreed to a change, the notice still must come, but not always before the change. The sources do not spell out the exact notice for a variable-rate change beyond that index exemption.
When a rate can rise on existing balances
The general rule is that an issuer may not raise the rate on a balance you already carry. The CFPB lists exceptions:
- A temporary or promotional rate that lasted at least six months has expired.
- A variable rate went up because its index went up.
- Your minimum payment was not received within 60 days after the due date.
- You completed, or failed, an arrangement to lower your rate.
Penalty APRs are a separate case. After a violation, such as going over your limit or a serious repayment problem, an issuer may apply a higher penalty rate. Federal law requires 45 days of notice, and the notice should state the penalty rate and the reason.
Introductory rates work differently too. If the promotion terms were disclosed up front, the rate can rise when the promotion ends without a new advance notice. Write down the end date the day you open the account.
How to check your own card
Take these steps in order. First, find out whether your APR is fixed or variable. The cardholder agreement says how your rate can change. It is usually on the issuer's website, and you can ask for a copy.
Second, look for any promotional rate, the date it ends, and the rate after that. Third, check cash advances on their own. They typically carry a higher APR than purchases and may have no grace period, which is the stretch where you owe no interest if you pay in full.
Fourth, keep every notice you get. If an increase on an existing balance seems to fall outside the exceptions above, the notice and agreement are your evidence. The sources I used do not cover disputes or complaints in detail. The CFPB's complaint process and your issuer are the places to start.
Why rate changes matter for budgets
Rates shape behavior. A Federal Reserve Bank of Boston analysis found that a 1 percentage point rise in card rates was followed by an 8.7 percent drop in card spending the next month. The scale is large. US consumers made $5.83 trillion in card purchases in 2022, about 20 percent of consumer spending.
Revolvers feel this most. A revolver is someone who carries a balance from month to month, so interest keeps accruing. If you pay the full statement balance each month, the rate touches you less. The timing rules still matter, though, so read your notices either way.
Please seek a professional. This article is general information, not financial, tax or insurance advice. Please seek a licensed financial, tax or insurance professional about your own situation.
