While he has built up a level of wealth to rival the budgets of some small states, Mr Charles (Chuck) Feeney does not apparently belong to the school of "if you have it, flaunt it".
Asked a few years ago to describe the publicity-shy American, one of his associates said: "He doesn't own a house. He doesn't own a car. He flies economy, and I think his watch cost about $15."
Senior academics here report the same. Often on his Irish visits, he has to be collected at the airport because he has no car and declines to hire one.
While business magazines have estimated his wealth in the billions, in the early 1980s he transferred virtually all of it into his philanthropic organisation, Atlantic Philanthropies.
Asked why, he replied: "I simply decided I had enough money."
Enough money may be an understatement when one considers that the asset base of his foundation, according to figures from March of last year, was $4.6 billion. According to reports in the US, he is now personally worth less than $5 million.
The rest of his fortune is dispensed, by a small team at the foundation, via donations around the world, with Ireland getting almost a quarter of the funds.
The businessman from New Jersey is understood to have ancestors from near the Border and is a close observer of the Northern peace process.