What would you do with a whopping $1.5 billion?

That will be the question on many Americans` lips Wednesday, when the draw is made for the largest lottery jackpot in US history.

Even after the taxman calls, the Powerball jackpot could make the lucky winner wealthier than the likes of football star Lionel Messi, Swiss tennis champion Roger Federer and US superstar Beyonce.

You can choose to be paid the full jackpot in annual instalments for 29 years -- or take $930 million as a one-off payment -- before taxes.

Record sales have driven up the bonanza, as people dreaming of riches flocked across state lines and international borders to snap up tickets, but lottery officials are not ruling out the prospect of the jackpot rising even further.

"The whole building`s putting in two bucks, so we`re all going to party down in the Caribbean and split the money," joked Mark Ferro, who works for a property management company, counting down the hours to the TV draw at 10:59 pm (0359 GMT Thursday).

"I`m going to buy a nice big house on an island," said his colleague John, an engineer who did not want to give his second name. The rest? He`ll give away to friends, family and charity.

The odds of winning are one in 292 million -- so remote that you are 246 times more likely to be hit by lightning, according to The New York Times, but punters refuse to indulge the killjoy tone.

"Everybody at work is just dreaming out loud and I actually said this morning I wonder how many offices are having the same conversation," said Marlene Rijo, 31, who works for a general contractor.

To win, a ticket holder has to match all numbers on six balls selected -- five white balls from a drum containing 69 balls, and one red one pulled from a drum with 26.

Since the last jackpot win on November 4, more than $1.75 billion worth of Powerball tickets have been bought, Gary Grief, executive director of the Texas Lottery and chair of the Powerball game group, told AFP.

"Sales are doing exponentially more than we`ve ever done before," Grief said.

"I`m hearing anecdotally and through news outlets, millions of people who have never played Powerball before are indeed purchasing a ticket."

Some retailers scoring the biggest sales are in US states bordering the handful that do not participate in the game, he said.

"People are flocking over from those states to stand in line and buy lottery tickets," he said.

"You do not have to be a citizen of the US -- people are coming from Mexico and Canada to purchase tickets."

But Grief sounded a note of caution.

"We want people to play responsibly. This is not a game to put your life savings on, your retirement on. A big part of the fun is putting down your $2 and then dreaming."

The lottery anticipates that 85 percent of all possible combinations will be wagered on so there is an 85 percent likelihood of a jackpot winner on Wednesday night.

The previous US jackpot record of $656 million, on March 30, 2012, was scooped by three winners from North Carolina, Puerto Rico and Texas.

The world`s richest lottery is Spain`s annual Christmas "El Gordo," which in 2015 handed out 2.2 billion euros ($2.4 billion) but which capped individual wins at 400,000 euros and handed out thousands of smaller prizes.