Battling CVR Energy, Wachtell, Lipton, Rosen & Katz argues it’s far too late for the Carl Icahn-controlled company to add new claims to its legal malpractice suit against the firm. Further, Wachtell claims, its own initial engagement letter with CVR was “too indefinite to be enforceable.”

Wachtell has been battling CVR Energy’s legal malpractice lawsuit for nearly five years. The refining and fertilizer company is alleging Wachtell failed to advise that CVR would face claims by Deutsche Bank AG and The Goldman Sachs Group Inc. for $36 million under the terms of engagement letters with the banks.