Caroline Kennedy's personal fortune could be worth as much as $500 million.

According to Kennedy's financial disclosure statement, revealed this week as part of her nomination as U.S. ambassador to Japan, it appears Kennedy has substantial holdings through family trusts and assets that range from investments in Apple and Goldman Sachs to commercial properties in Chicago and Washington and elsewhere.

The New York Post the estimates in 2008 suggested that Kennedy could be worth anywhere between $100 million and $250 million. But according to paperwork she filed last month, that number could be substantially higher.

'She’s very rich, probably worth between $250 million and $500 million,' a source told the Post. '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 reportedly reveal 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 an income of almost $1 million annually from speaking engagements and royalties from books.

The revelations come five years after Kennedy refused to release her financial information during her bid to take over Hillary Clinton’s US Senate seat. After it became an issue she subsequently withdrew her request for then Governor David Paterson to appoint her to Clinton’s seat. (Had she been running for office Kennedy would have been required to report her assets, credit card debt, mortgages and income from sources that total more than $5,000.)

Details of Kennedy's extensive fortune emerged after she filed documents with the US Office of Government Ethics for her nominated role as Ambassador to Japan.

In a letter Kennedy reportedly explained, 'I understand that a heightened prospect of a conflict of interest could exist as to companies that maintain a presence in Japan.'

To offset any claims in this area she has agreed to 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 for the ambassadorship.

Caroline Bouvier Kennedy, a member of the influential Kennedy family and the only living child of U.S. President John F. KennedyGoogle Images