Card Activation Technologies Inc. is suing five more merchants.

The Chicago processing technology vendor said Tuesday that it had filed patent infringement lawsuits against Panda Restaurant Group Inc., Casual Male Retail Group Inc., BeBe Stores Inc., Whole Foods Market Inc., and Barneys New York Inc.

The suits, filed last week in the U.S. District Court for the Northern District of Illinois in Chicago, allege that the retailers are using the vendor's patented technology for activating and using prepaid cards.

Card Activation Technologies has filed 12 such suits in the past two years.

Of the seven filed before last week, it has settled all but two, against Barnes & Noble Inc. and Aeropostale Inc. The vendor announced settlements this month with OfficeMax Inc. and Sears Holding Corp.

It also said Tuesday that it has told over 600 merchants that their gift card programs may be infringing on its patents.

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