Prince Harry will become entitled to part of the inheritance left to him by his mother Diana, Princess of Wales when he turns 25 next week.
It is understood the third in line to the throne will, for the moment, not touch the money.
Like his brother Prince William, Harry was left £6.5 million in the princess's will following her death in a car crash in 1997.
A Clarence House spokesman said: "We don't discuss Prince Harry's private financial arrangements."
Diana had an estate of £21 million, but more than £8 million was paid in inheritance tax, leaving £12,966,022.
It was split equally between William and younger brother Harry.
Through investments, it is likely to have grown substantially since the princess's death 12 years ago.
But it is not known how or if the economic downturn has affected the amount.
Changes agreed to the will in December 1997 meant that, upon reaching 25, William and Harry would be entitled to the whole of the income of their share.
Before the age of 25, income could be paid at the trustees' discretion.
The trustees can pay over capital at any time, but when the princes turn 30, they can ask for their share of the capital in full.
The princess's estate was made up of stocks and shares, jewellery, her multi-million pound divorce settlement, dresses and personal items from Kensington Palace.
Harry is currently training to become an Army Air Corps helicopter pilot, and as a Lieutenant in the British Army is on a pay band of £29,006 to £32,061.
Born on September 15 1984, he was christened Prince Henry Charles Albert David at St Mary's Hospital, Paddington and will celebrate his birthday next Tuesday.
He trained to become an officer in the Army at the Royal Military Academy Sandhurst, joining the Household Cavalry and served in Afghanistan for 10 weeks last year.