All six children of David Rockefeller, the oldest Forbes 400 member, have signed too.

FORBES: Weak Estate Tax Could Derail Tax Deal

David Rockefeller Sr. is the only living grandson of Standard Oil founder John D.

FORBES: Billionaires Hall Of Fame

David Rockefeller collected and later filled his headquarters, 1 Chase Manhattan Plaza, with contemporary art.

FORBES: What $100 Got You In 1954: Lessons In Art And Growth Stocks

Other billionaires who have pledged large sums of their money include film producer George Lucas, philanthropist David Rockefeller and oil investor T Boone Pickens.

BBC: US billionaires pledge 50% of their wealth to charity

"We are in this for the long term and have experience with multiple generations, so the name should be useful as a symbol of continuity, " says David Rockefeller Jr.

FORBES: Old money chasing new

Only David Rockefeller of that clan has created more wealth through the development of Rockefeller Center and the success of the Chase Bank, now part of JP Morgan Chase.

FORBES: The Getty Genius Moves On From Oil To Digital Media

Thirteen of the 16 billionaires who have hit age 90 built their fortunes themselves--the three exceptions being U.S. oil-family scion David Rockefeller, Danish shipping-company executive Maersk Mc-Kinney Moller and Saudi banker Saleh Al Rajhi.

FORBES: Magazine Article

The area, which runs east from Central Park past ritzy Park Avenue apartment houses to the East River, and north from 60th Street to 69th, is home to such plutocrats as David Rockefeller, Rupert Murdoch, Ronald Perelman, Robert Bass and Sumner Redstone.

FORBES: Manhattan's Now Home To America's Most Expensive Zip Code