A Texas pipeline tycoon who died two months ago may become the first
American billionaire allowed to pass his fortune to his children and
grandchildren tax-free. When John D. Rockefeller, America’s first
billionaire, died in 1937, his estate paid 70 percent.  But Dan L. Duncan, a Texas natural gas billionaire who owns natural gas processing plants and pipelines, died in March, 2010, at age 77, making him the first known billionaire to die during the year without an estate tax.  If congress does not act to make the estate tax retroactive into 2010, the federal treasury may miss out on as much as $4 Billion in estate taxes.  The Treasury collected more than $25 billion in estate taxes in 2008,
the most recent year for which data is available. More.