Wealthy denizens of Hollywood and Silicon Valley — an elite strata not always held in the highest esteem by the general public — have pledged large donations amid the global economic chaos to help those afflicted by the coronavirus.

“If anyone can afford to give right now, it’s the billionaire class,” says David Callahan, founder and editor of news site Inside Philanthropy.

Big-check writers have included CEOs like Amazon’s Jeff Bezos, Facebook’s Mark Zuckerberg and Comcast’s Brian Roberts; billionaire entrepreneurs Bill Gates and Michael Bloomberg; and celebs Oprah Winfrey and Rihanna. Then there’s Twitter CEO Jack Dorsey, who has outdone everyone by pledging $1 billion in proceeds from stock sales of his payments company Square — nearly one-third of his wealth — to create a fund initially focused on COVID-19 relief efforts.

It’s a historic outpouring of financial support from leaders in media and tech, and could herald more to come, says Kris Putnam-Walkerly, a philanthropy consultant and author of the recently published book “Delusional Altruism.”

Dorsey’s $1 billion pledge “is so staggeringly large,” she says, that it could put pressure on other high-net-worth individuals to give more. That said, the vast majority of billionaires are not publicly disclosing if or how they are giving in response to the global health crisis. It’s safe to assume many billionaires are not making any charitable gifts to address the pandemic.

Affluent donors have a long track record of stepping forward with assistance during crises, Callahan says. Contributions flowed after 9/11, as well as natural disasters like the recent California wildfires. Bezos in February announced a $10 billion fund to fight climate change. “The difference with this [pandemic] is that it’s far bigger than anything in recent memory and comes at a moment when the wealthiest Americans have more money than ever,” Callahan says.

Is there more behind the phenomenon than simply trying to help? Dorsey, in a Twitter thread, wrote: “The needs are increasingly urgent, and I want to see the impact in my lifetime. … I hope this inspires others to do something similar.” The 43-year-old exec also expressed a doing-well-by-doing-good motive, explaining the fund should benefit both Twitter and Square over the long term “because it’s helping the people we want to serve.” (Dorsey, through a rep, declined an interview request.)

In addition to individual contributions, tech giants and others are seizing the moment to burnish their brands as good corporate citizens. Apple has procured and is distributing 20 million protective face masks; the company also brought together teams across Apple and its suppliers to design, produce and ship about 1 million face shields weekly for frontline health care workers. Google, Facebook and TikTok have established funds to assist smaller businesses with cash grants and ad credits.

Amid the surge in giving, history suggests that overall philanthropic efforts likely will decline, despite a bump in corona-virus-related donations, says Jane F. Karlin, an adjunct associate professor at the NYU School of Professional Studies Center for Global Affairs. During the recession of 2007-10, total charitable giving in the U.S. dropped by 10.9%. The reason? Americans gave nearly the same proportion of their income as before — but “many saw their incomes decline during the recession,” she says.

With the spread of the coronavirus evolving so rapidly, it’s not always clear what the best uses of philanthropic funds are, Putnam-Walkerly says. There are obvious immediate needs, but COVID-19 recovery efforts will stretch on for years.

“There will also be a need for philanthropists to support long-term recovery, reform and resilience,” she says, “long after this crisis [is out of] the headlines.”