The royal family is reportedly worth $23 billion — King Charles III, 73; and Prince William, 40; are both billionaires after Queen Elizabeth's II death.

The exploding growth of royal wealth is the fastest it has ever been, doubling in the past 10 years according to The Sunday Times of London.

The rich continue to get richer, as "The Firm" — King George VI's nickname for the monarchy — holds estates and properties since Edward the Confessor acquired them nearly 1,000 years ago.

Among the most valuable properties are the Crown Estate (worth $18 billion alone) and the Duchies of Lancaster and Cornwall, which have doubled in 10 years, hundreds of miles of British coastline, the Ascot racecourse, and the Oval cricket ground.

The Crown Estate is actually controlled by the British Treasury and the new King Charles has no power to sell holdings or receive income from it, according to the report. He will receive a percentage of the profits.

Charles inherited the Duchy of Lancaster estate, including 45,092 acres of land in Cheshire, Lancashire, Yorkshire, Lincolnshire, Derbyshire, Staffordshire, and South Wales. Others expected to pass to Charles include the 20,000-acre Sandringham Estate in Norfolk and the 50,000-acre Balmoral castle.

The inheritance of the British monarchy is not public record, as established by a court in 1820, according to the Times.

Among the other royal family members, according to the report:

• William inherits the Duchy of Cornwall.
• Princess Anne, 72, is worth an estimated $52 million, owning Gatcombe Park and the 700-acre Gloucestershire mansion.
• Prince Andrew, 62, the queen's second son, is worth less than $8 million, having settled his civil suit against Virginia Giuffre for an estimated $10 million.
• Prince Edward, 58, and his wife, Sophie, are worth around $12 million.
• Prince Harry, 38, and his wife, Meghan Markle, are worth an estimated $22 million, the Time said.

• Queen Stayed Above 'Political Fray,' Maintained US-UK's 'Special' Relationship
• Queen's 8 Grandchildren Hold Silent Vigil Beside Her Coffin

• King Charles III Oversees $42 Billion in Assets