"It's the fault of the banks - they shouldn't have allowed people to over-extend themselves as much as they did," said the Englishman who went to prison for bringing down Barings Bank.
"They actually promoted it as far as I'm concerned, and they are the engineers of their own demise."
Like all businesses in recession-hit Ireland, soccer is suffering. "It's extremely difficult. The amount of discretionary spend out there is very limited," Leeson told Reuters in an interview at the west-coast League of Ireland club.
"As bad as everything is in the country, the soccer clubs are struggling more," said Leeson, looking healthier and heavier than when he was released from jail in 1999 suffering from colon cancer.
"There's a similarity with the football clubs at the moment - you've just got too laden with debt, you reach an extreme limit and you just can't operate any more.
"You can't get any more credit, the interest on the money you owe keeps increasing at a rate you can't keep pace with."
Leeson was a Singapore-based junior derivatives trader when he ran up a $1.4-billion loss that led to the 1995 collapse of British merchant bank Barings.
He spent three-and-a-half years in a Singapore jail, emerging to write a book entitled "Rogue Trader" which was later made into a film with Ewan McGregor as Leeson.
Now 43, he joined Galway five years ago and lives on the outskirts of the city with his second wife and their children, combining working for the small club with speaking engagements.
Asked about plans for his future at the club, Leeson said: "I don't know, but I see myself staying in Galway; it's a lovely place to live and the family are happy here."
Despite the unsteady financial climate, and football's battle in Ireland to prize spectators from rugby and the national sports of Gaelic football and hurling, Leeson said the country's clubs offered a good investment opportunity.
Of the 10 teams in Ireland's top division, four will qualify for European football next season.
"The multiple millions you could invest in a Championship club in England... you could invest a small fraction of that in Ireland and qualify for Europe.
"It depends what people's motivations are, and if it's to own a club in England then so be it. But if it's to qualify for the group stages of a European competition there are other ways of investing your money. You get more bang for your buck here."
Historically, Irish clubs have helped to make ends meet by selling players to teams in England but that revenue has also begun to feel the squeeze.
"We've got two or three players that are attracting a lot of interest from the U.K., Germany, Cyprus and Greece, but it became very apparent to me during the summer that there's a glut of professional footballers out there," Leeson said.
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