Five years after Caroline Kennedy refused to release financial information during her bid to take over Hillary Clinton’s US Senate seat, newly filed documents reveal a personal fortune that could be as high as $500 million.

Very private Kennedy declined to release the data in 2008. She subsequently withdrew her request for then-Gov. David Paterson to appoint her to Clinton’s seat. (If she had been running for office, Kennedy would’ve been required to report assets, credit card debt, mortgages and income from sources that total more than $5,000.)

But now, Kennedy has had to file documents with the US Office of Government Ethics for her nominated role as Ambassador to Japan.

Estimates in 2008 were that Kennedy could be worth anywhere between $100 million and $250 million. But, according to paperwork filed by Kennedy last month, that number could be even higher. “She’s very rich, probably worth between $250 million and $500 million,” said one legal eagle who reviewed the publicly available documents. “From the figures, it looks like she earns between $12 million and $30 million a year from her trust and from her investments.”

The documents reflect that beyond her holdings in family trusts, she has positions through Phil Falcone’s Harbinger Capital, Apollo, Goldman Sachs, Vornado Realty Trust, JP Morgan, Blackstone and the Arctic Royalty Limited Partnership, which reportedly relates to two family-owned oil companies.

She also reports almost $1 million annually from speaking engagements and royalties from books.

In a letter Kennedy also explains, “I understand that a heightened prospect of a conflict of interest could exist as to companies that maintain a presence in Japan.” She goes on to say she’ll step down from roles with the Institute of Politics at Harvard, the Kennedy Library Foundation, the Kennedy Center for the Performing Arts and her husband’s Edwin Schlossberg Foundation if she’s confirmed. Kennedy could not be reached for comment.