Credit Suisse Group AG entities, one of six defendants in a lawsuit originally filed by Iowa Public Employees Retirement System and other retirement associations, has agreed to pay $81 million, becoming the first to agree to settle, the law firm Cohen Milstein Sellers & Toll PLLC said in a release.

"This first settlement agreement includes both an $81-million cash payment and an obligation on the part of Credit Suisse to provide cooperation to plaintiffs in litigating and ultimately trying their case against the remaining defendants," lawyers for the plaintiffs said in a court filing late on Friday.

The plaintiffs had accused units of Credit Suisse, Goldman Sachs Group, JPMorgan Chase & Co and three other banks of conspiring since 2009 to keep the stock lending market "in the stone age" by boycotting startup platforms like AQS or Data Explorers. They accused the banks of doing this in order to charge investors excessive fees.

Credit Suisse said in a statement that it believed the plaintiffs' claims were without merit, but "we are pleased to resolve the litigation."