Life-insurance proceeds, gifts and inheritances are also not subject to the tax, nor are appreciated assets donated to charity.

WSJ: Are You Ready for the New Investment Tax?

Other advantages: By making Giving Back a public charity rather than a private foundation, Pollick avoids a 2% federal excise tax on assets, while donors get a bigger tax writeoff if highly appreciated assets are donated.

FORBES: Savior To The Stars

Given that one of the tenets of Shariah-Compliant Finance is the system of zakat in which 2.5% of assets are donated to charities chosen by Shariah scholars, this story raises significant questions about the due diligence and disclosure practices of Shariah finance.

CENTERFORSECURITYPOLICY: The Mumbai terrorists, zakat and charities

And it's not as though the money will sit gathering dust in the coffers of Gates' charity: Buffett wants all his money to be distributed in the year it is donated, not added to the foundation's assets for future giving.

FORBES: Magazine Article

Under shariah compliant finance, 2.5 percent, or one-fortieth, of the assets of the financial instrument have to be donated each year to zakat.

CENTERFORSECURITYPOLICY: Center For Security Policy