NEW YORK - At this time last year, Caroline Kennedy was promoting "A Family Christmas," a collection of essays that featured the memory of her father letting her use the White House switchboard to call Santa.

This year, after warily stepping into the political free-for-all for Sen. Hillary Rodham Clinton's job, Kennedy's activities during the holiday season included fending off requests to disclose financial information.

The calls for Kennedy to release her financial information, required of many public officials including her uncle Massachusetts Sen. Edward Kennedy, come after a lifetime of carefully cultivated privacy.

By all accounts a very wealthy woman who could be worth as much as $400 million, Kennedy has said that she will not release details of her finances unless Democratic Gov. David Paterson picks her for the Senate seat that will open up if Clinton is confirmed as secretary of state.

Before she announced her interest in Clinton's Senate seat, the 51-year-old lawyer, author, wife and mother had been largely invisible to most Americans, who knew her better as the precocious preschooler from John F. Kennedy's administration.

Estimates of Kennedy's wealth vary. The Daily News of New York added up assets in the public record and came up with a net worth that tops $100 million. But in his 2007 book "American Legacy: The Story of John and Caroline Kennedy," author C. David Heymann estimated that Kennedy is worth more than $400 million.

When her mother died in 1994, executors valued the Onassis estate at $43.7 million, a figure that has risen after auctions of various assets. Kennedy and her brother, John F. Kennedy Jr., also inherited their father's share of the large, undisclosed fortune founded by their grandfather, Joseph Kennedy. John F. Kennedy Jr. died in 1999 and left an estimated $50 million estate, with his sister and her children as beneficiaries.

Kennedy and her husband, museum designer Edwin Schlossberg, live on Park Avenue in a prewar co-op building where a neighbor's five-bedroom apartment was recently listed for $13 million. Kennedy also owns a 366-acre estate on Martha's Vineyard in Massachusetts that she inherited from her mother. The property's worth is estimated at $50 million or more.

Kennedy's spokesman, Stefan Friedman, said Wednesday that she will comply with applicable financial-disclosure laws if she is appointed to the Senate but will not release tax returns.

Senators are required to file financial disclosure statements each year. Her uncle is estimated by the Center for Responsive Politics to be the seventh richest member of Congress, possibly worth $103.5 million or more. *