They feel duped. They have lost substantial amounts of cash. And now an angry group of US retail investors is urging greater regulatory scrutiny over what they see as deceptive governance practices on the part of several mostly Greek public shipowners doing business with US investment bank the Maxim Group.

The effort is being led by Kalle Ahl, a Colorado-based investor who says he lost about $25,000 on shares of Performance Shipping when he was too late to recognise signs that management was willing to let the stock price plummet to achieve its aims.