American Express market share 18 per cent

American Express has put its market share in Australia in July 2010 at 18.3 per cent.

This is less than the 20.0 per cent reported on Tuesday, a number that's formally related to the three-party card scheme but is essentially American Express.

Amex reached the lower number through a different treatment of the restatement of data in May, to exclude scheme debit transactions, though only from 2008.

MWE Consulting principal, Mike Ebstein, yesterday refreshed his estimate of three-party card schemes.

"The bottom line is that the trend has been accelerating since the series break occurred," Ebstein wrote in an email.

MWE estimates Amex share as:

•  3-party share July 2008, 17.3%

• 3-party share July 2009, 17.9%

• 3-party share Jul 2010, 20.0%

Almost all this market share, and all the growth, is for American Express.

American Express points out that the base for comparison on Tuesday, of 12 per cent, was too low.

"In January 2002, American Express' market share (combined with Diners) as reported by the Reserve Bank of Australia tables was 13.8 per cent - not 12 per cent," Nic Frankham, director of public affairs for Amex, wrote in an email.

The removal of scheme debit cards from RBA data lifted the combined American Express and Diners Club market share from 15.8 per cent to 17.5 per cent.

Amex estimates its growth in market share at 4.5 percentage points, a one-third rise over four years.

And Amex is the only real winner from payments reform.