Henri-Paul Rousseau, former president of the Caisse de depot et placement du Quebec, appeared Tuesday in front of a National Assembly committee trying to establish why and how the Caisse lost nearly $40 billion last year.

Rousseau said one of the problems was that the Caisse did not know exactly how deeply it had invested in a risky investment vehicle called asset-backed commercial paper, or ABCP.  The commercial-paper fund has been been frozen and can't be cashed in due to concerns that ABCP was tied into the U.S. sub-prime mortgage housing crisis.

Rousseau did not offer an explanation, or an apology when asked how such key financial institution such as the Caisse could have failed to keep track of its investments.

Changing his tune?

In March, when Rousseau spoke to a group of business elites at an event hosted by the Board of Trade of Metropolitan Montreal, he said it was his decision to invest so heavily in ABCP.

"I take full responsibility," he told the room in French.

At that time, he also said the losses were on paper, and the Caisse's coffers would fill out again when the market rebounded. He indicated he believed the problem was mostly due to the faulty international economy rather than poor management of the Caisse.

In his final full year at the head of the Caisse, Rousseau earned $1.8 million. Of that, more than $700,000 was a performance bonus.