St George Bank is gaining so much ground as a MasterCard issuer and ANZ is giving up so much groundÂ- that St George may now be the fourth largest issuer of MasterCard branded credit cards in Australia.Evidence in the ongoing Federal Court hearing into MasterCard's and Visa's joint effort to overturn the Reserve Bank's regulation of the sector discloses that the top four MasterCard issuers account for 94 per cent of all MasterCard transactions. This is no great surprise, given big banks are generally known to control 90 per cent plus of the credit card market and have done for years.However, the twist is that if the fourth of the four banks is excluded from this calculation (and this bank must be ANZ), and St George Bank's MasterCard share is added back, then the combined share is still in excess of 90 per cent.Although the exact market shares of ANZ and ST George weren't disclosed in the cross examination, St George must have somewhere between four per cent and five per cent (leaving room for BankWest's growing MasterCard portfolio), and must be nearly as large as that of ANZ Bank.And it seems that on recent trends, it is likely that St George will displace ANZ Bank as the fourth largest MasterCard issuer (measured by card spending) by the end of the 2002/2003 financial year (ie. in a few weeks).ANZ's tiny MasterCard issuing business is also no great surprise, given the bank's historic preference for Visa card, the dominance of its Qantas ANZ Visa co-brand card, and the bank's move to substantially increase the interest rate on what used to be the bank's "low interest" MasterCard product. That move in turn was related to the bank's desire to drive demand for its "First" branded credit cards, with a chip (which now has is ANZ's low interest rate offer), as well as MasterCard's removal of the "net issuer" rule which used to cost ANZ Bank $1 or $2 million a year in penalty payments.A further twist to this shift in ranking of MasterCard issuers, however, is the implications for the review of interchange fees that gets underway in a few weeks.Its looks like the review will examine the combined credit cost structures at ANZ, Commonwealth, National and Westpac in order to establish interchange fees for Visa cards and Bankcard, but may will exclude ANZ and instead include St George to determine interchange fees for MasterCard.