$59 trillion to go to heirs, charity by 2061

The greatest wealth transfer in history is underway, according to a new report.

A study from the Boston College Center on Wealth and Philanthropy projects that $59 trillion is expected to be passed down to heirs, charities and taxes between 2007 and 2061.

The study said heirs will receive $36 trillion over that period, while federal estate taxes will receive $5.6 trillion.

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Total gifts to charity during the period of the study are expected to be more than $27 trillion, which includes sums from final estates (with no surviving spouse) as well as total lifetime giving.

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The study assumes economic growth rates of 2 percent and the extension of current tax provisions. If the economy grows at 3 percent a year, charitable giving could reach $40 trillion, according to the study.

"The estimates of wealth and philanthropy we highlight in the report are conservative and probably represent the floor rather than the ceiling of what is in store for philanthropic giving," said Paul Schervish, director of the Center on Wealth and Philanthropy. "The most important finding in the study is the continued abundant and growing financial capacity for philanthropy."

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The estimate marks a big increase from Schervish's previous projection and is likely to spark new debate. In 1999, Schervish co-authored a study with John J. Havens predicting that between 1998 and 2052, at least $41 trillion would be passed down. The number was hailed by many in wealth management and philanthropy circles, but greeted with skepticism by others.

Michael J. Weiss wrote in Ad Age that the "impending generational transfer of wealth in America may be more myth than reality" because of a weak economy, sputtering stock market and faltering Social Security system.

Russell N. James III penned a critique in the American Review of Public Administration called "The Myth of the Coming Charitable Windfall," saying that estate gifts are largely offset by a reduction in current giving.

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An analysis done by Edward Wolff at New York University and Maury Gittleman at the U.S. Bureau of Labor Statistics in 2011 found that "there is little evidence of an inheritance 'boom.'" In fact, between 1989 to 2007, the share of households reporting a wealth transfer fell by 2.5 percentage points.

Of course, the future will tell. But so far, forecasts of a giant wealth cascade to heirs and charity have yet to materialize.

—By CNBC's Robert Frank.