Sam Morgan has made as much from his stake in Xero as he did from selling Trade Me, he reveals in an exclusive interview.

The 30-year-old with the Midas touch made $227 million when he sold Trade Me to Fairfax Media in 2006. He then bought a stake in accounting software firm Xero before it listed in 2007.

When Xero floated 27 per cent of the company on the NZX at $1 a share, it raised $15m. Shares were trading at $43.45 yesterday, valuing the company at about $5 billion.

"People were really impressed when we sold Trade Me for $750m, but Xero is six or seven times that size, it's a big deal," he said.

His millions have allowed him and father Gareth - whose stake in Trade Me netted him about $47m - to live the dream by helping others through projects such as the Morgan Foundation.

Father and son joined forces recently on a two-week mission to the sub-Antarctic islands to promote, among other things, Gareth's "million-dollar mouse" campaign to eradicate pests from the Antipodes islands.

Gareth Morgan said: "I feel I'm incredibly lucky having so much money. It's ridiculous, so I figure there's no [point] in earning more money - that doesn't spin my wheels any more, and this other stuff does, it's incredibly satisfying."

Sam, who still drives a Volkswagen Golf, has about 20 projects on the go in the developing world, mostly focused on alleviating poverty.

He has no interest in starting another business, which he says takes a level of obsession which only those who have done it can fully understand.

"I spent 10 years basically only thinking about Trade Me. It's all I thought about.

"Literally, the last thought in my head when I went to sleep at night was something to do with Trade Me. The first thought in my morning, before thinking about brushing teeth or breakfast, or your wife or your kids or anything, was Trade Me."

Having financial security means he, wife Talei Hayward and their two daughters don't share some of the concerns of the people around them, "but you've still got all the other same problems".

"Most of life I think doesn't really change, but anything to do with money . . . you sort of need to recognise that you don't have the same level of problems as ordinary people do with mortgages and affording a holiday once a year or whatever, those become non-problems.

"But everything else is pretty much the same, you know. The dishwasher still doesn't empty itself."

Living in New Zealand, where people were sensitive to "big noting", helped to keep life normal.

"In New Zealand, if you're wealthy, people note it but it doesn't significantly impact how they interface with you. People still treat you the same.

"The US is unbelievable like that. If you're a billionaire, you actually have a different god . . . you've almost reached immortality."

His father shares his taste for simple cars, driving a Toyota Yaris. He says of Sam: "He's a good boy, he's bloody bright, he's very clever - don't tell him that, though. He has a superb brain."