HANGZHOU, April 25 -- The founders of Chinese Internet giant Alibaba announced on Friday they will set up a charitable fund.

Chinese Internet entrepreneurs Jack Ma and Joe Tsai said the personal charitable trust will be funded by 2 percent of Alibaba's equity, which they received as share options in the company last year.

Alibaba announced in March its plans to go public in the U.S. The company's valuation has been estimated at between 100 billion and 200 billion U.S. dollars.

Based on the estimation, Ma's foundation is expected to boast funding between 2 billion to 4 billion U.S. dollars, equivalent to the yearly fiscal revenue of a Chinese prefectural-level city.

Ma said in an exclusive interview with Xinhua that he has not decided on the name of the foundation, but it will focus on environmental, medical, educational and cultural programs in China and overseas.

"My wife and I had this thought of setting up a personal charitable fund when we started the business. We'd like to earn money before we turn 50 years old and do charitable work in our time after 50," said the billionaire, who will turn 50 in September.

He left his position as Alibaba's CEO last year. In the same year, he served as a chair of the U.S. Nature Conservancy's China board of directors.

Ma said the four areas the foundation will focus on are the issues people in China are most concerned about. For example, people rarely heard about cancer over a decade ago, but today, everybody knows someone suffering from cancer.

"It is impossible for me to be a doctor. But I can have my own way to save lives," Ma said.

Ma's philanthropic vision has won the support of Western business leaders.

Bill Gates, co-chair of the Bill and Melinda Gates Foundation, said that Ma's and Tsai's generosity, leadership and example will "do an immense amount of good, particularly in this remarkable time in the development of philanthropy in China."

Warren Buffett, Trustee of the Bill and Melinda Gates Foundation, said Ma and Tsai have been "extraordinary leaders in business and have now become leaders in philanthropy."

Wealthy Chinese businessmen have been criticised by the public for their lack of philanthropic conscience.

Ma said that, compared with capital, philanthropic work in China is "more lacking in institutional building and personnel training."

"Charity work in China has just set off. We are learning, and we will do more when we gain experience," he said.

Ma personally retains 7.3 percent of the equity of Alibaba, which has been keen to expand out of its core online retail business to shopping malls, home appliances, mapping services and financial services through a series of acquisitions since last year.