PURCHASE, N.Y. — MasterCard International has taken steps, which it hopes will placate merchants and take some wind out of the sails of its critics.

Merchants and sympathetic lawmakers have been complaining that both Visa's and MasterCard's regulations and interchange rates are too complicated and not transparent. Now MasterCard has announced that it will publish all the interchange rates that apply to U.S. merchants taking their cards and will cap the interchange charged to petroleum retailers.

Card brand critics have suggested that Visa and MasterCard have kept the interchange rates too secret and petroleum retailers have recently been complaining about the additional cost of interchange in the face of higher gasoline prices.