The practice was confined to only small to mid-size businesses.

As per a report from the Wall Street Journal citing sources familiar with the matter at hand, American Express Co raised currency conversion rates for business clients without notifying its customers in advance; AmEx’s move was aimed at boosting its employee commission and revenues.

The practice, confined with its forex department, has been in practice since at least 2004 to early 2018, said the report which mostly small to mid-size businesses.

Incidentally, American Express’ forex business accounts for less than half of a percentage point of its total revenues, said the WSJ.

American Express did not immediately respond to a request for comment.