Washington - A U.S. agency says consumers who opt for overdraft coverage on their checking accounts pay higher fees and are more likely to have their accounts closed than those who decline it.

A report by the Consumer Financial Protection Bureau released Tuesday says it's hard for consumers to anticipate and avoid overdraft charges. It found that the cost for "opting in" for overdraft coverage varies widely from one bank to the next.

Customers of some banks paid average charges of $298 annually, while those at others paid $147.

The CFPB has been investigating overdraft fees, which are a major source of banks' revenue. The agency has said its examination could result in new rules.

The Consumer Bankers Association, which represents large U.S. banks and regional banks, urged the CFPB not to adopt any policy that it said could push consumers toward financial firms outside the banking industry which are less strictly regulated by the government and offer costlier alternatives.

"Consumers have the right to choose the products and features which best provide for their family's daily financial needs," Richard Hunt, the group's president and CEO, said in a statement Tuesday. "Fortunately, the marketplace for checking accounts is extremely competitive and banks make every effort to educate their customers about the options available to them."

Banks charge overdraft fees when customers try to spend more money than they have in an account.

Banks will allow the transaction and then charge the customer a penalty of as much as $35.

Consumer advocates say overdraft fees hurt the people who can least afford them because poorer customers are more likely to drain their checking accounts.

"...We are concerned that some overdraft practices may increase consumer costs beyond reasonable expectations," CFPB Director Richard Cordray said in a statement. In 2010, the Federal Reserve barred banks from automatically enrolling customers in so-called overdraft protection programs for debit card or ATM transactions. Banks must obtain a customer's consent, or "opt-in." Without overdraft protection, a transaction is declined if the customer can't cover it. The rule didn't apply to checks, online bill payments or recurring debits, such as a monthly cable bill. It also didn't limit how much banks can charge for the overdraft service.

Banks have responded by marketing overdraft protection aggressively.

Negative account balances can lead to involuntary closures of accounts, which can leave a black mark on a consumer's record and make it hard to open a new account, the report noted. It found that involuntary closure rates at some banks were over 2.5 times higher for customers who had opted for debit and ATM overdraft coverage.

The overdraft fees are complicated, the report said, and vary widely among banks.