Mr Cuban's lawyer Robert Hart was famously involved in what is believed to be the largest purchase conducted over the net, without a written contract - the 1999 US$41m acquisition of a Gulfstream V private jet. Robert Hart said: 'There was no hand-signed contract. It was a transaction done completely over the Internet. Mark had already wired the money, and I was trying to catch up. It was very scary buying the plane over the Internet because that big of a financial transaction had never happened before.'

GC to 100 organisations

Mr Hart is, in effect, personal counsel to Mr Cuban - handling all tax, insurance and HR issues for the 100 or so companies owned by the entrepreneur as well as sitting on the board of the stadium which is home to the Dallas Mavericks on his behalf. A particularly famous Cuban venture is the reality TV programme Shark Tank.

Satan..my Satan

Interviewed about his dealings with Mr Hart and other lawyers, the entrepreneur said: 'Do I like dealing with lawyers? No. I hate it. I absolutely hate it. We’ve become such a litigious society that it is a huge drain on productivity. Lawyers may be Satan, but Robert is my Satan, and I trust him completely. He’s not only a trusted adviser, he’s a good friend.'

Bracewell & Giuliani

The two men first met at a party in 1987 when the lawyer was an associate at Bracewell & Giuliani and the entrepreneur said he needed legal advice on financing a house purchase. Source: Dallas News