Britain's Prince Harry poses with Meghan Markle in the Sunken Garden of Kensington Palace, London, Britain, November 27, 2017.
Britain's Prince Harry poses with Meghan Markle in the Sunken Garden of Kensington Palace, London, Britain, November 27, 2017. Reuters/Toby Melville

Prince Harry probably won’t share his wealth with Meghan Markle after they married. The prince, who is estimated to be worth tens of millions, is not expected to give his soon-to-be-wife any money, lest the entire British royal family’s fortune is exposed to American tax.

The 33-year-old younger son of Prince Charles and the late Princess Diana is estimated to be worth AU$51 million, which included half of his mother’s £21.5 million (AU$37.14 million). The other half of the wealth, of course, went to his older brother, Prince William. Harry also shares £3.5 million (AU$6.05 million) annual allowance with William and wife Kate Middleton.

Markle, 36, isn’t exactly hurting for cash either. The American actress is said to be worth around US$5 million (AU$6.39 million) from her “Suits” TV show salary, other acting engagements, and sponsorship and endorsement deals. As an American citizen, she pays taxes in her home country. That is unlikely to change even after marrying Harry in May.

Although she intends to be a naturalised British citizen, the process will finalise after she has lived in the UK for at least three years. There will be no shortcuts as well, as Jason Knauf, Harry’s communications secretary, previously said she would be “compliant with immigration requirements at all times.” It’s unclear whether she would opt for double citizenship, though.

She will be required to continue paying tax to the Internal Revenue Service (IRS) in the US unless she renounces her US citizenship. But it’s certain that for three years during the naturalisation process, she will retain her US citizenship.

Even after her wedding to a British royalty, Markle will pay income tax as long as she is a US citizen. If she received money from Harry or the royal family, it would be considered income, then she would have to pay tax on that, royal expert Marlene Koenig told The Sun.

If she has more than US$300,000 (AU$383,000) worth of assets in any given year, she would need to file Form 8938 document, which would reveal the details of these assets. This could potentially expose details of the British royal family’s previously undisclosed estate.

“Prince Harry receives no public funding,” Koenig said. “But it is possible there may be other family trusts that he receives from – we don’t know officially if the Queen has set up trusts for her grandchildren – it is possible. It’s the same thing with some of the Queen Mother’s money. There were rumours that there were different trusts set up, but that’s not public information. With that sort of money, if Meghan’s name is on that account, most likely she would be dinged – that would have to be reported as income in the United States.”

The Buckingham Palace would doubtfully let this happen, though. Koenig said those who run the royals’ accounts were looking very carefully into the matter to make sure the Queen and the family’s fortune would not be reported to the IRS.

It would be a different scenario if Harry moved to the US with Markle. He would not be expected to pay taxes in Britain.

If the couple were to have children, their kids would be US citizens. Unless the children decided to renounce being American citizens when they reached the age of majority, they would have to pay taxes in their mother’s native land as well.

The figures mentioned above are only estimates, particularly Harry’s wealth. Apparently, even the Queen herself may not even know how much the family is really worth. Author David McClure told the Washington Post in November that their finances have long been “impenetrable” to outsiders. “I suspect the Queen doesn’t know,” he said.