In the six years since Woolworths launched its Everyday Money Credit Card it has managed to build a card balance of just A$350 million.This figure is based on data in the Australian Prudential Regulation Authority's latest banking statistics, which show that in May Macquarie Bank's credit card portfolio jumped by A$350 million to $655 million, while HSBC's card portfolio fell $368 million to $869 million.These changes followed the announcement by Woolworths that it was changing its credit card partnership arrangements from HSBC and MasterCard to Macquarie and Visa.Woolworths entered the credit card market promoting a rewards program that would make it "easy to earn points and easy to redeem rewards". Its point of difference was that cardholders were issued with shopping cards automatically every four months, carrying the value of their accumulated points, which they could use to make purchases in a range of Woolworths group stores.A balance of $350 million after six years must make other retailers, such as Coles, wonder whether it is worth getting into retail financial services (the market leader, Commonwealth Bank, has an $11.3 billion card portfolio).