Indian-American Silicon Valley venture capitalist Vinod Khosla and his wife Neeru are among the latest billionaires to have pledged half of their vast fortunes to charity either during their lifetime or after death.
Ten more families, including the Khoslas, signed the pledge on April 28, bringing the total number of signatories to 69.
Several of Silicon Valley's leading entrepreneurs, including venture capitalist John Doerr, Oracle CEO Larry Ellison, hedge fund manager Tom Steyer and Facebook's Mark Zuckerberg have previously signed on to the pledge.
"I am delighted that so many wealthy Americans are taking a public pledge that supports philanthropy," Warren Buffett, pledge co-founder and the chairman and CEO of Berkshire Hathaway, said in an April 28 statement.
Fifty six-year-old Khosla is Silicon Valley's most prominent "green" venture capitalist and a dominant personality in the cleantech community. A co-founder of Sun Microsystems, Khosla was a general partner at VC firm Kleiner Perkins Caufield & Byers before striking out on his own with Khosla Ventures in 2004.
The Sand Hill Road firm focuses on cleantech and information technology start-ups, with a portfolio that includes carbon sequestration and storage, solar, batteries, biofuels, building materials, energy efficiency and next-generation lighting and appliance companies.
Khosla is keenly interested in funding technologies that can be widely adopted in fast-growing India and China, what he regularly refers to as the "Chindia test."
As of March, Khosla's net worth was $1.4 billion, according to a calculation by Forbes.