Between 1998 and 2004, the number of main credit and charge cards in has more than doubled, from about 1.245 million to 2.986 million, and since the end of 2004, the number has doubled again. Professor of Finance Benedict Koh called this development, ?quite staggering'. Furthermore, the rollover balance has more than doubled since 2004, from S$2.64 billion to about S$4 billion. Professor Koh added: It's almost like a bubble trajectory, and that's quite worrying. Banks are very happy to encourage you to keep the balance outstanding. It's a loan shark rate, too - the effective rate is about 26.8 per cent.