These were the golden years, culminating in 2005, when Gudmundsson received Iceland’s Knight’s Cross Order of the Falcon from President Olafur R. Grimsson for his contribution to society.

The next year, Gudmundsson spent 85 million pounds ($128 million) on an 83 percent stake in West Ham, and in March 2008, newspaper Morgunbladid estimated his personal fortune at $1.1 billion. Seven months later, his investment in Landsbanki soured as the lender collapsed. The credit event triggered a claims dispute from depositors based in the U.K. and Netherlands with savings in the bank’s high-yielding Internet accounts.

When global financial markets froze at the end of that year and Iceland’s banks were shut out of funding markets, everything came tumbling down.

Gudmundsson, then chairman at Landsbanki, told a Reykjavik court his assets had plunged the equivalent of $1.1 billion in value. His $759 million personal bankruptcy plea in 2009 was the biggest in the nation’s history, according to Iceland’s Legal Gazette.

Retail ‘Kingdom’

In an interview outside his house in Reykjavik, Gudmundsson ascribed his sudden accumulation of wealth before the crisis to “a certain situation in the economy” at the time. He declined to elaborate.

Johannesson, who in a March 2012 interview revealed plans to build what he described as a new retail “kingdom” in the U.K., was sued by the caretakers of failed Glitnir Bank hf, the lender that financed most of his ventures. His personal fortune -- which peaked at $1.6 billion in 2007, according to Frettabladid, which he owned at the time -- had dwindled to about $2 million, he said last year.

Johannesson, now 45, started his career more than two decades ago, opening a chain of Bonus supermarkets in Iceland in 1989 with his father. By borrowing against equity in his existing business, Johannesson financed purchases of U.K. brands, including toy store Hamleys Plc and department store House of Fraser Ltd. Both have since been sold off to cover debts.

‘Past Mistakes’

Johannesson, in the March 2012 interview, said his biggest mistake was to continue expanding after buying Big Food Group Ltd. in December 2004 for 326 million pounds. Last month, Iceland’s Supreme Court found Johannesson guilty of nine violations, including tax fraud. On top of a prison term, he was fined 62 million kronur ($497,000). The 12-month sentence was suspended for two years, meaning he can avoid going to jail if he doesn’t break the law during that period.