The Senate proposal was brokered between Republicans, who say lenders should be able to take into account a person's behavior, and Democrats, who contend that the practice of hiking rates on past balances prevent consumers from climbing out of debt.
The agreement was included as part of a broader package on credit card reform, announced Monday by Senate Banking Committee Chairman Chris Dodd, D-Conn. The bill was expected to pass this week with President Barack Obama's support.
Dodd had originally proposed an outright ban on retroactive rate increases. But without Republican support, his bill was considered unlikely to overcome procedural hurdles in the Senate.
The latest proposal would prohibit lenders from increasing interest rates on past buys unless the cardholder has fallen at least 60 days behind. At the same time, lenders would be required to review a cardholder's terms every six months.
"It makes a strong point to the industry that if they are going to change the terms of a card based on (risk) factors, it should be a two-way street," said Nick Bourke, manager of the Safe Credit Cards Project at the Pew Health Group.
Under the request by Republicans, the bill also would require the Federal Reserve to report to Congress every two years on the cost and availability of credit.
"Should this legislation become law, it is crucial that Congress carefully monitor its implementation and effect to ensure that this balance in design is also a balance in fact," said Sen. Richard Shelby of Alabama, the top Republican on the Banking Committee.
Senate Majority Leader Harry Reid told reporters on Monday that he thinks Republicans are jumping on board because they don't have a choice.
"I think they've come to the realization that there are a lot of good things they can be involved in. They can go home and take credit for helping us do this," said Reid, D-Nev.
Reid said the recent party switch by Sen. Arlen Specter, D-Pa., also has forced Republicans to become "more realistic."
Debate on the bill comes as the Center for Responsible Lending estimated that some 10 million cardholders have seen their interest rates increase in the last six months for no particular reason. Many cardholders have seen increases of 10 percentage points or more, the group says.
The Senate bill would require that promotional rates last at least six months. It also prohibits rate increases in the first year after an account is opened.
Other provisions in the bill would:
The bill would go into effect nine months after enactment. The Housein April by a 357-70 vote.