Here's how much of their wealth some of the richest Silicon Valley billionaires are donating to fight the coronavirus

Jack Dorsey

Silicon Valley billionaires are collectively pledging billions of money from their personal fortunes towards relief funds against the devastating impact of the coronavirus.
This week, Twitter CEO Jack Dorsey announced he was donating $1 billion towards a relief fund, which he said is roughly 28% of his net worth.
Other execs have pledged hundreds of millions of dollars, but compared to their net worth this may not be as much as it seems.
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As the coronavirus outbreak has spread, tech companies and their executives have hastened to donate medical supplies and cash.

Companies including Facebook, Apple, and Tesla have pledged millions of dollars in the form of both cash and medical resources like masks, protective gear, and ventilators.

Individual executives are also kicking in. Bill Gates, who founded his philanthropic organization the Bill and Melinda Gates Foundation 20 years ago, has been particularly vocal about the crisis, and Twitter CEO Jack Dorsey this week announced he was setting up a $1 billion fund.

But to Silicon Valley billionaires, who make up some of the world's richest individuals, even enormous sums of money can make up only a fraction of their net worth.

Here is a breakdown of how much money four tech billionaires have pledged versus how much their estimated net worth is, per the Bloomberg Billionaires Index.

Jack Dorsey

Estimated net worth: $3.89 billion

Amount pledged: $1 billion

The Twitter CEO announced on Tuesday he was donating $1 billion in equity from his digital payments company Square to a relief fund called "Start Small." Dorsey said it will initially focus on coronavirus relief, but will in time move towards funding girls' health and education.

Dorsey published a link to flow tracker with the fund. At time of writing, it shows $100,000 is earmarked for America's Food Fund.

According to Dorsey, the fund constitutes roughly 28% of his net worth.

San Francisco Chronicle reporter Owen Thomas wrote this isn't the first incarnation of the Start Small fund. He points out that Dorsey made a promise in a 2015 SEC filing for Square that he would donate millions of shares into the Small Start fund, but that as of 2018 they had not materialized in the public record.

Thomas also points out that as an LLC fund the money is not yet committed, and can return to Dorsey at any point.

Jeff Bezos

Estimated net worth: $123 billion

Amount pledged: $100 million

Jeff Bezos announced in early April he was donating $100 million to Feeding America, a nonprofit focused on supporting food banks.

At time of writing Jeff Bezos is the world's richest person with an estimated $123 billion, meaning $100 million would make up roughly 0.08% of his fortune.

"Even in ordinary times, food insecurity in American households is an important problem, and unfortunately COVID-19 is amplifying that stress significantly," Bezos wrote in an Instagram post.

Meanwhile, Bezos' company Amazon has set up its own relief fund for its contractors and seasonal workers, kicking in an initial $25 million and opening the fund up to outside donations.

Bill Gates

Estimated net worth: $101 billion

Amount pledged: $100 million

Gates' philanthropic organisation The Bill and Melinda Gates foundation pledged $100 million towards fighting the pandemic in February, which constitutes 0.99% of Bill Gates' personal wealth.

In March, the Gates Foundation said it would contribute $50 million towards a joint fund with Wellcome and Mastercard called the "COVID-19 Therapeutics Accelerator", which combined would hold a $125 million pot. It is not clear whether that $50 million came out of the initial $100 million pledge or not.

The foundation is also funding at-home coronavirus tests in Washington State, and Gates says it will help fund the construction of seven factories to manufacture potential candidates for a vaccine, even though at most one vaccine candidate would be selected.

Mark Zuckerberg

Estimated net worth: $65 billion

Amount pledged: $25 million

Zuckerberg's philanthropy organization the Chan Zuckerberg initiative announced in March it was donating $25 million towards the Therapeutics Accelerator set up by the Gates Foundation, Wellcome, and Mastercard. This makes up just under 0.04% of Zuckerberg's estimated net worth.

Following the donation a TikTok video illustrating how little of Zuckerberg's wealth $25 million makes up went viral.