Highland Capital Management's draft lawsuit against George Economou and his public and private companies has laid out a laundry list of ways that the financial firm alleges the Greek shipping mogul siphoned cash out of drilling contractor Ocean Rig and into both shipowner DryShips and his own pockets.

One of the Dallas asset manager allegations is that after Ocean Rig purchased the drilling rig Cerrado for $65m in an auction in Brazil last year, the proceeds were ultimately used to pay off a debt to Economou — chief executive of the Nasdaq-listed driller and DryShips — that was owed by the rig's former owner, Schahin Oil & Gas.