Plaintiff credit unions include the $155 million Matadors Community Credit Union of Chatsworth, Calif., $2 billion GECU of El Paso, Texas, $2 billion MidFlorida Credit Union of Lakeland, Fla., and the $4.2 billion Pennsylvania State Employees Credit Union of Harrisburg, Pa.

Legal experts have said the Heartlands case may be impacted by a U.S. Supreme Court decision in late 2013.

Known as the “Clapper decision,” the case of Clapper v. Amnesty International USA raised the barriers to commencement of a successful class action for a breach of data security, according to a Lexology post submitted by the law firm of King & Wood Mallesons.

Since the Clapper decision was handed down, courts have dismissed the vast majority of data breach class actions, the post said.

In the Heartland case, U.S. District Judge Lee Rosenthal, who is currently presiding over the litigation in Southern Texas, dismissed most of the complaints filed by the financial institutions in late 2011.

In that case, Rosenthal ruled that the plaintiffs were not specifically protected in contracts between Heartland Payment Systems and its acquiring banks, Heartland Bank and KeyBank, and that the financial institutions were not covered in contracts between Heartland and the major card brands. The credit unions and banks appealed, targeting the negligence and responsibility for losses.

A panel of the Fifth Circuit Court of Appeals in New Orleans ruled last fall that the credit unions and banks could state a claim for negligence because the economic loss doctrine did not apply, despite the fact that the card issuers lacked a written contract with Heartland. Litigation was then consolidated into one complaint to be heard by Rosenthal.

While the legal war wages on, Heartland Payments has been working to restore its image and launch new products. The company recently unveiled a new service called Heartland Secure, which utilizes encryption, tokenization and a proprietary EMV-compliant point-of-sale terminals, according to Heartland's website. Heartland Secure will be offered free of charge to Heartland merchants, the company said.

In addition, Robert O. Carr, CEO of Heartland, delivered a keynote presentation at the 7th Annual Mobile Payments Conference Oct. 8 in Chicago, according to national media.

“We created Heartland Secure to provide customers with a secure solution for POS and other card processing methods, which can help prevent data breaches and other potential liabilities, including astronomical fines and damage to brand reputation,” Carr said in the MarketWatch article.

He added, “The number of security breaches in the retail industry has reinforced the need for merchants to incorporate more than one technology solution to payment transaction security.”