Some sources claim the Duke of Sussex may have been left more money than his older brother in the inheritance.
Prince Harry is reportedly set to inherit £8 million ($17m) from the late Queen Mother when he turns 40.
The Duke of Sussex will celebrate the milestone on September 15, and it is thought his grandmother, the late Queen Elizabeth, started collecting a huge trust fund for him when he was aged 10.
At the time, the Queen Mother, who was then 94, apparently put aside a tax-free £19 million ($40.4m) to leave to her great-grandchildren, according to the Times.
The newspaper added the inheritances were divided into two installments – one to be given to Princes William and Harry when they turned 21, and another on their 40th birthdays.