The rogue trader's earnings (About $100,000 annual salary plus bonus):

1997: $102,000 1998: $232,102 1999: $226,441 2000: $186,000 2001: $332,000 ($220,000 bonus not paid)

"We believe we do understand the fraud and where it led," said the man in charge of the team of investigators, Eugene Ludwig, who used to work in the administration of former US president Bill Clinton.

"The fraud was carefully planned and meticulously implemented by Mr Rusnak, extended over a lengthy period of time, and involved falsification of key bank records and documents," said the in-house report.

The basic idea of his ploy was fairly simple.

Mr Rusnak initially sold himself to the bank as a trading expert who could consistently make money from complex currency derivative trades.

This involved buying currency options where the risks were supposed to have been offset by separate currency trades.

But instead he went on to make large but relatively simple one-way bets, the report said.

These bets were not hedged, and when they started going wrong Mr Rusnak invented bogus option trades to hide his losses and the size of his positions.

"The fictitious options also tended to give the appearance that his real positions were hedged," the report said.

Acting alone

But although the investigators blame Mr Rusnak, they also criticised his immediate bosses for failing to supervise his supposed hedge-fund style trades.

"The Allfirst treasurer and his treasury funds manager - the principal persons responsible for Mr Rusnak's supervision - failed for an extended period to monitor Mr Rusnak's trading," the report said.

Allfirst's treasurer David Cronin and five of his colleagues were fired following the investigation.

Mr Rusnak "liked to be wined and dined"

Senior Allfirst and AIB executives were also criticised in the report for their reliance on the Allfirst treasurer.

"In hindsight, this heavy reliance proved misplaced," it said.

But the investigation did not find any evidence that anyone at AIB or Allfirst, with the exception of the US subsidiary's treasury group, were aware of or involved in the "improper trading activity".

Allfirst's chairman, Frank Bramble, will retire early in June, although AIB stressed that he had no knowledge of the affair.

Nobody at the highest level within either AIB or Allfirst have been fired over the affair.

The treasurer

The investigation into the causes of AIB's losses uncovered a range of problems within the Allfirst subsidiary.

The investigation found that Allfirst's chairman Frank Bramble and chief executive Susan Keating, as well as AIB Group executives, had "found the treasurer's energy and commitment levels to be wanting" and there had been talk of changing his reporting line or removing him.

Mr Bramble and Ms Keating had also been critical of the way Mr Cronin had defended his head of treasury funds management, Bob Ray, against accusations of bullying.

The trader

The rogue trader Mr Rusnak was also seen as a bully by some.

Back office staff "found him to be arrogant and abusive", the report said.

But he was popular within the financial market where "brokers and traders heavily entertained [him] with meals, hotel stays, golf trips, Super Bowl tickets and other travel."

"He apparently liked to be wined and dined, and the brokers obliged," the report added.

Mr Rusnak was also seen as a strong and confident family man who "appeared to be living a lifestyle consistent with the level of his reported compensation."

Mr Rusnak's annual salary of about $100,000 was supplemented by a bonus directly linked to his net trading profits.

This usually doubled his annual earnings, although last year he did even better.

In 2001, he clocked up a $220,000 bonus on top of his $112,000 salary, but the bonus was withheld when the trading losses were discovered.