The Logothetis family is waging a legal battle with German banking giant Nord/LB in a dispute over discounted shipping loans.
The New York-based group has alleged that its financier reneged on an agreement to provide a $22m discount on $84m-worth of loans relating to seven containerships.
The dispute marks a low ebb in a 16-year relationship during which time the partners have conducted nearly $2bn of business.