LONDON - British bookmakers installed George and James as the favourites on Monday for the name of the new royal baby boy after a bumper day of betting on the new arrival.
The majority of punters were left disappointed when Kensington Palace revealed the arrival of a son, confounding pre-birth expectations of a female newborn.
According to Mr Rory Scott, a spokesman for Irish bookmakers Paddy Power, around 60 per cent of gamblers had bet on a girl or on a girl's name.
The firm had earlier paid out on a girl after Kate appeared to stop herself from saying she was looking forward to giving a present from a well-wisher to her daughter.
"It's been bonkers," Mr Scott told AFP. "We have taken about £50,000 (S$97,000) today." "I think everyone's got sunstroke, we've had a pramload of bets."
George is now the Paddy Power favourite at 6/4 followed by James (11/4), Alexander (7/2) and Louis (8/1).
But James, the name of Kate's brother, is the "red-hot" favourite with Ladbrokes, although Henry's odds have been slashed from 50/1 to 5/1.
"We're staring down the barrel of a gun if the baby's named Henry," said the firm's Jessica Bridge.
"It's been odds-on all year long that Kate would give birth to a girl and punters who believed it would be a boy have now collected over £100,000 worth of winnings."
At the other end of the spectrum, Wayne is trading at 250/1 - although a bet was earlier placed on Kai, the name of footballer Wayne Rooney's son, at 1000/1.
The palace said on Monday that the "names of the baby will be announced in due course." Meanwhile a new market has opened on exactly when the baby will be named.
It was a month before the baby's grandfather, Prince Charles, was named - but Ladbrokes say it is odds-on that the name will be announced on Tuesday.
"But for those who think we could be waiting a week like William's announcement can take odds of 3/1," they added.
There are plenty of more offbeat bets to be had.
Paddy Power is offering odds of 7/4 that the future king's first word will be PaPa and 10/11 that he'll follow in his uncle Harry's footsteps and have his first nightclub visit before his 17th birthday.
Ladbrokes if offering odds of 4/7 that William will come out of hospital holding his newborn, shorter than the 6/4 offered on Kate.
Bookies say they have taken more than £1 million in total on what they have called the biggest novelty (non-sporting) market of all time.
Bets have come in from around the world with one lucky Austrian man placing £1,000 on a male baby.
Scott said the amount of money is "quite staggering" and compared to what would be placed on English football's FA Cup final.
Firms suspended the betting on Monday as the birth date once the Duchess of Cambridge was in labour.
In the run-up it was an unpopular choice of day, though.
"The 17th was the most popular. Only five per cent of the bets were placed on today - today was an outsider," said a William Hill spokesman.
"Everyone seemed to think that the baby would come last week." Even after the birth there will be no rest for the betting firms, with people now betting on Kate's sister putting in an appearance.
"We are running bets now on the colour of the dress Pippa will be wearing on her first visit to the hospital and how many times Pippa will run the media gauntlet, how many times she will enter in the hospital and who will be holding the baby on the steps. The current favourite is William," Mr Scott said.
And the betting bonanza could go on for years - firms are already taking wagers on baby number two.