Transfer fees are becoming a feature of credit card balance transfer deals, with several issuers charging one per cent to move balances. Citibank upped the ante earlier this month when it set a fee of three per cent for customers transferring existing credit card balances into its platinum rewards credit card.A couple of years ago Citibank made a push for more retail banking market share with a range of low and no-fee products. Now the strategy seems to have changed.Citibank's balance transfer deal is no interest for 24 months, before reverting to a purchase rate of 20.99 per cent.According to Infochoice.com.au, Westpac introduced transfer fees early last year and American Express introduced them this year. Both Amex and Westpac charge one per cent to transfer.A consumer transferring their balance to Westpac's 55 day platinum Visa pays a one per cent transfer fee and gets a rate of 3.99 per cent for six months, before reverting to a standard purchase rate of 19.99 per cent. There must be a customer value proposition in their somewhere.