WASHINGTON – Former New York Mayor Michael Bloomberg stumbled in Wednesday night's Democratic debate in response to a question about when he planned to release his tax returns.

"It just takes us a long time," Bloomberg said.

"Unfortunately, or fortunately, I make a lot of money and we do business all around the world, and we are preparing it. The number of pages will probably be thousands of pages. I can't go to TurboTax," Bloomberg added.

The remarks, which gave the impression that he was bragging about his wealth, drew boos from the audience in Las Vegas. Nevada holds its Democratic caucus on Saturday. He was already taking a beating from his rivals, including Sens. Elizabeth Warren and Bernie Sanders.

"But I put out my tax return every year for 12 years in City Hall," he said. "We will put out this one, it tells everybody everything they need to know about every investment that I make and where the money goes and the biggest item is all the money I give away."

Bloomberg is the wealthiest candidate in modern times to mount a viable campaign for president, and has so far spent more than $400 million of his own fortune on ads, despite not appearing on any ballots so far. He is worth about $60 billion.

But the question of his taxes is one that could haunt Bloomberg if he were to be the Democratic nominee in a general election. President Donald Trump long vowed to release his tax returns, but has yet to do so, claiming that he is under a constant state of audit that prevents him from making the returns public.

In 2016 Trump was the first major party candidate in nearly 50 years not to release tax returns to the public.