Caroline Kennedy has revealed her financial information in order to be considered as the next American ambassador to Japan, and it is believed she may be worth up to $500 million.

Caroline Kennedy’s wealth has been a closely-guarded secret for decades, but now that President Barack Obama has nominated her to represent the US abroad, she has to list the sources of her massive income.

“She’s very rich, probably worth between $250 million and $500 million,” said one legal expert who had seen the financial disclosure forms.

Caroline Kennedy, who is the sole surviving member of former President John F. Kennedy’s immediate family, has avoided calls to publicly release her financial statements in the past, but as the Senate must now approve her appointment to be an Ambassador, she has no choice.

The closest she came to revealing her millions came in 2008 when she asked then-New York Governor David Patterson to suggest she take over Hillary Clinton’s empty Senate seat.

At the time, Caroline Kennedy said she would reveal what board positions make her how many millions and exactly how much her family trusts earn in interest, but only if her takeover of the Senate seat was going to happen.

It didn’t, so the curtains surrounding her bank accounts remained closed.

Now there is no such justification for privacy, as she needs to reveal what ties she will be willing to cut in order to take the prestigious position.

“I understand that a heightened prospect of a conflict of interest could exist as to companies that maintain a presence in Japan,” Caroline Kennedy wrote in a letter accompanying her disclosure statements.

According to The New York Post, said conflicts could include a number of board and trustee positions that she olds with Harvard University’s Kennedy school, her husband Edwin Schlossberg’s foundation, and the arts foundation created by her mother and father.

Caroline Kennedy has revealed her financial information in order to be considered as the next American ambassador to Japan

The biggest source of her income is from the extensive trusts that her grandfather Joe established for each of his children and grandchildren.

The untimely deaths in Caroline Kennedy’s family have led to a piling up of respective estates, as her mother Jackie inherited her father’s trusts after he was assassinated in 1963.

After leaving the White House, Jackie Kennedy married Greek shipping magnate Aristotle Onassis in 1968, though he died less than seven years later in 1975.

When he passed away, Jackie Kennedy was not entitled to as much as she would have been as a result of Greek estate laws, and after two years she agreed to accept a $26 million settlement from her late-husband’s daughter Christina in return for giving up all claims to the family fortune in the future.

People Magazine reports that Jackie Kennedy’s later relationship with financial planner Maurice Tempelsman helped her build that payout from the Onassis family into an estimated fortune of anywhere between $100 million and $200 million, though it is unclear where that money went exactly as her final estate that was passed on to her children was significantly lower.

Jacqueline Kennedy was diagnosed with cancer in 1994 and died four months later. She left her children an estimated $43.7 million, including several pricey properties including her 15-room apartment on Fifth Avenue which had a view of the Metropolitan Museum of Art, as well as the 366-acre Kennedy estate on Martha’s Vineyard.

In May of this year, Caroline Kennedy listed 90 waterfront acres of the property for sale – with no homes included – for $45 million though it does not appear to have sold yet. She is still holding on to three lots of land for herself and her children, two that pay off the cost of estate expenses, and one that has been designated as open space. The Boston Herald reports that the lots she is keeping for her family include the home that her mother lived in and designed.

This isn’t the first time that Caroline Kennedy has made a parcel off her mother’s property. Jackie Kennedy bought the 15th floor of her Fifth Avenue apartment on Manhattan’s Upper East Side in 1964 following the president’s assassination, she paid $250,000. It sold for $9.5 million in 1995 after her death to billionaire David Koch.

“Mrs. Onassis was very conservative financially, and she didn’t spend much on it. We gutted the apartment and redid everything,” he said to The Observer after he decided to sell it for $32 million in 2006.

On top of her own piece of the Kennedy pie, Caroline also inherited her brother John Jr.’s trusts when he died in a plane crash in 1999.

John Kennedy Jr. left his $50 million to his relatives and a few charities, but the Kennedys are also believed to have paid the Bessette family $15 million as a result of the crash. He was the one piloting that fatal flight in his plane with his wife Carolyn and her sister Laura as passengers; investigations into the crash reported that all three died on impact and the cause of the crash was pilot error.

“From the figures, it looks like she earns between $12 million and $30 million a year from her trust and from her investments,” an unidentified legal expert told The Post.

The interest yielded from those funds is hefty, but Caroline Kennedy, 55, has not just been resting on those laurels.

She has stakes in banks like Goldman Sachs, Blackstone, JP Morgan and two oil companies that her family’s assets own.

On top of those eight-figure sums, she also brings in an additional $1 million from paid speeches and book royalties on a yearly basis.

Caroline Kennedy has been a perpetual consideration for a number of political posts over the years, but this one comes at a personal cost as her husband Edwin Schlossberg will not be joining her in Tokyo since his design firm is based in New York.

Their 26-year marriage has been the subject of speculation over the years since they are rarely seen together, but they were seen enjoying a beach vacation in St Bart’s over the girls’ spring break earlier this year.

If the nomination goes through, Caroline Kennedy will become the first woman appointed to the post.