According to the Duchy of Cornwall estate’s 2023 annual report, Prince William received a private income of nearly £6 million this year—which converts to more than $7.5 million.

The 41-year-old inherited the estate after his grandmother, the late Queen Elizabeth II, died and his father King Charles III ascended to the throne—and is now entitled to its surplus profits every year.

But because the prince became heir to the throne halfway through the financial year, this year’s income is just a fraction of what he could have earned.

The Duchy generated record profits of £24.05 million in 2022-23—a jump of about 4.5% from £23.02 million the year before. It means that next year, even if the estate’s profits stagnate, the future King of England could rake in over $30 million.

William won’t be telling you how he’s spending the income

The annual figures which were published on Thursday, are usually accompanied by a separate annual report detailing the broad income and expenditure of the Duchy money.

King Charles—who was the former Duke of Cornwall—released his household’s financial review on Thursday. However, Prince William has opted not to. 

Kensington Palace, Prince William and Kate Middleton’s Royal residence and press office, said that the past year had been a transitional one following the death of the late Queen and as such they would not be releasing a report this year, according to the Daily Mail.

But the move is attracting criticism, particularly from a leading figure in the Republican movement, which aims to abolish the monarchy. 

“William has some explaining to do because a change of monarch and heir is no excuse to row back on what little transparency there is,” Graham Smith, chief executive of Republic, reportedly said.

“There is absolutely no reason why William’s household cannot provide a full set of accounts for this financial year. As the recipient of public funds from the state-owned Duchy, he should be reporting his income and expenditure.”

He went on to suggest that the eye-watering high profits generated from the Duchy of Cornwall estate would be better spent on “local communities”.

“It’s time we demanded the return of the Duchies (of Cornwall and Lancaster) to the people,” he reportedly added. 

The Duchy was essentially created to support the heir to the throne

Valued at more than £1 billion, The Duchy of Cornwall is one of the UK’s largest and oldest landed estates—it extends across 23 counties in England and Wales and includes the Oval cricket ground and 67,000 acres of Dartmoor.

It was established in 1337 by King Edward III to support his son and heir Prince Edward, known as the Black Prince, and all his subsequent heirs. Today, that hier is Prince William and as such, he benefits from the Duchy income. 

It’s unclear precisely what Prince William will do with the multimillion-dollar income, but according to the Duchy of Cornwall’s official website, the revenue is usually used to fund the public, private, and charitable activities of The Duke and his immediate family—including his wife and three children. 

What’s more, the heir to the throne has no access to the Duchy’s capital value and pays income tax on the annual revenue surplus he receives from it.

Kensington Palace did not immediately respond to Fortune’s request for comment.