Can my credit card issuer reduce my credit limit?
Credit card companies generally can increase or decrease credit limits without giving you notice, including reducing your credit limit so that you no longer have any available credit. If you no longer have any available credit, you cannot make any charges until you pay off some of your existing balance.
If a card issuer decreases your credit limit, the card issuer cannot charge you over-the-limit fees or a penalty rate for exceeding your new, lower credit limit, until 45 days after it has given you notice of the decreased credit limit. A card issuer cannot charge you over-the-limit fees if it didn’t give you notice of the decreased credit limit or if you haven’t opted in to the payment of over-the-limit transactions.
Don’t get too close to your credit limit. Experts advise keeping your use of credit at no more than 30 percent of your total credit limit. This can help you avoid problems if your credit limit is lowered. It can also help you keep a good credit score.