As Comptroller, Thompson promised that New York City pension fund money would be used to develop jobs and businesses in Northern Ireland once appropriate investing guidelines were met.
However a New York Times investigation revealed that no money was spent there and that a firm set up to create investment opportunities took $3million in fees and delivered nothing. Emerald Infrastructure Development Fund was a Cayman Island registered company with no expertise whatsoever in Northern Ireland.
Worse for Thompson, a close associate and placement agent William Howell earned a $250,000 fee.
On Thursday Christine Quinn questioned Thompson's money-management skills.
"It's an example of taxpayers' money being lost and this loss of taxpayer money follows on the heels of the CityTime losses, (a plan to overhaul how city financial records were kept which ran way over budget) and I think it's yet another example of things in the comptroller's office falling through the cracks, not being appropriately taken care of when Bill Thompson was [there]," she said.
"I think that is a record that the voters need to look at," said Quinn. "We now have more than one example of taxpayer money being lost, while Comptroller Thompson was the comptroller. And it really raises a question of what was going on in that office, who was or was not in charge."
Thompson shot back in response to Quinn: "I am more than happy to talk about people's records; I'm proud of mine. As Comptroller, I led efforts to increase the city pension funds by $20 billion. While I was doing that, Chris Quinn was using a corrupt slush fund to park taxpayer dollars in phony charities to buy political support and running the City Council budget in a way that rewarded her friends and punished those who disagreed with her."
The two candidates are expected to face each other in a run off on October 1st for the Democratic nomination after the September primary.