The Board is amending Regulation Z, which implements the Truth in Lending Act, and the staff commentary to the regulation in order to implement provisions of the Credit Card Accountability Responsibility and Disclosure Act of 2009 that go into effect on August 22, 2010. In particular, the final rule requires that penalty fees imposed by card issuers be reasonable and proportional to the violation of the account terms. The final rule also requires credit card issuers to reevaluate at least every six months annual percentage rates increased on or after January 1, 2009. The final rule also requires that notices of rate increases for credit card accounts disclose the principal reasons for the increase.