updated 07/15/2014 AT 2:00 PM ET
•originally published 07/15/2014 AT 3:30 PM ET
Just as birthday cards for Prince George are set to fly through the letter box at Kensington Palace, eager royal fans are wondering when a little sister or brother may join him in the palace nursery.
A British bookmaker is encouraging that speculation – a firm called Coral halted all bets on the possibility of the Duke and Duchess of Cambridge announcing baby number two this month, after a series of bets were placed online Monday night.
“When bets come in at once late in the evening, it sets alarm bells off,” Coral’s Nicola McGeady told PEOPLE. “It’s been quiet and then all of a sudden, a week before Prince George’s birthday, this happened. The bets sealed our opinion that someone knows something we don’t.”
Coral was offering odds of 10-1 on Kate announcing a second pregnancy in July. But the odds were cut to even money before the firm pulled the plug entirely.
Kate, 32, is likely ignoring the speculation as tiresome. She has other things on her mind. She will leave George at home when she heads off on her first solo tour to Malta in September.