The Business On... Mark Cuban, Owner, Dallas Mavericks

The NBA basketball team?

Indeed. Which is exactly the sort of plaything you might buy if you were made a dot.com billionaire overnight.

Dot.com billionaire? Thought they lost all their money?

Not if they happened to sell to a big sucker such as Yahoo at the height of the bubble. Mr Cuban, an entrepreneur and investor in Dallas, sold Broadcast.com, an online radio venture, for $5.7bn in 1999

Another case of a disastrous investment in sport?

No, no, no. Mr Cuban's ownership of the Mavericks has kept him in the limelight, he has plenty of money he keeps throwing into new ventures, and he is counted at No 400 on the Forbes list of global billionaires.

But is he happy?

Loving the celebrity life. He was even on Dancing With the Stars, a US Strictly Come Dancing. He just has a few anger management issues to sort out. He keeps shouting at basketball officials, rival teams, even players' mothers. He's been fined $1.6m for it so far.

What's he in the news for?

A little spot of difficulty with the authorities and an insider trading allegation that won't go away.

Details, please

Mr Cuban had a 6 per cent stake in an internet search company called Mamma.com when the chief executive told him, in 2004, that it was about to do a fundraising that would dilute shareholders. He sold his stake before the announcement, saving what would have been a $750,000 loss when the shares fell.

Open and shut?

Actually, the Securities & Exchange Commission's charges were dismissed by a judge last year, who agreed that, since Mr Cuban hadn't promised to keep the conversation secret, it wasn't insider trading. He accused the SEC of pursuing a vendetta.

So, why are we still talking about this?

An appeals court reinstated the case, so Mr Cuban will have to defend himself again. His NBA punishments could pale in comparison if he fails.