Another group of Japanese investors has sued Mitsubishi UFJ Financial Group’s joint brokerage venture with Morgan Stanley in the latest litigation over losses on Credit Suisse’s riskiest debt, which became worthless.

A suit representing 26 plaintiffs seeking to recover losses from so-called Additional Tier 1 (AT1) notes sold to them by Mitsubishi UFJ Morgan Stanley Securities was submitted to the Tokyo District Court on Tuesday. The plaintiffs are seeking a combined ¥1.73 billion ($12.2 million) in compensation according to the filing, which is led by Yamazaki Marunouchi Law Office.

A representative of the company, jointly owned by Japan’s largest lender and the major U.S. investment bank, wasn’t immediately available for comment. Two of the plaintiffs are companies, according to the complaint.