Sealink Funding, an Irish firm created to manage residential mortgage-backed securities, escalated its fight against U.S. banks over losses on RMBS investments by filing a $948 lawsuit against dozens of financial institutions.

The defendants include Countrywide, Royal Bank of Scotland (RBS), Deutsche Bank (DB), Citigroup (C), JPMorgan Chase (JPM), Wells Fargo (WFC) and HSBC (HSBC) and others.

Sealink previously sued RBS over investments that soured. In that suit, the company said it acquired $90 million in RMBS from Royal Bank of Scotland that included alleged misrepresentations about the underwriting standards used on the loans pooled into securities.

The company also sued Bank of America (BAC) over $1.6 billion in RMBS tied to 30 offerings in 2005 through 2007. In addition, Sealink sued JPMorgan Chase over $2.4 billion in RMBS purchased during the same time period.