But tech companies’ ability to decide what they contribute and don’t contribute to communities on their own terms may be ending. In San Francisco, Mountain View, and East Palo Alto, ballot referendums would impose additional taxes on big companies to solve problems related to a lack of affordable housing and funding for transportation. And tech companies are being forced to ask themselves whether they’re willing to play an active role in changing their neighborhoods, not just the world at large.

“We have to come to some kind of reckoning that when you make millionaires out of people, and they buy houses for millions of dollars, other people are going to be on the end of that,” Glenn Kelman, the president and CEO of Redfin, which has offices in Seattle and San Francisco, told me about tech leaders. Redfin opposed the Seattle head tax, but Kelman declined to sign a business petition against it, saying that businesses needed to step up to fund homelessness programs.* “We’ve always viewed ourselves as the hero of every story, and we’re about to see that we may be the enemy of this one.”

In San Francisco, voters are being asked to approve Proposition C, which would levy a tax on businesses with receipts of more than $50 million to fund housing and homelessness services. In Mountain View, it’s Measure P, a per-employee tax on companies with more than 5,000 employees; Google, which has more than 20,000 employees, could be saddled with about $3.3 million annually. And in East Palo Alto, residents are voting on Measure HH, which would charge companies with more than 25,000 square feet of commercial office space a tax of $2.50 per square foot to raise money for affordable housing and job-training programs. The tax could hit Amazon, which is opening new facilities there.

For decades, tech entrepreneurs have portrayed themselves as change agents creating world-altering products and then using their wealth to advance liberal policies. Yet their philanthropy is often focused on big projects that have national or global impact. When it comes to paying higher taxes to fund local projects, some companies have begun acting less like revolutionary organizations that are changing the way society works and more like, well, companies: opposing new local taxes based on the argument that they will hamper their ability to do business.

The initiative that has drawn much of their opposition is Proposition C, in San Francisco. If passed, it would levy a tax of 0.175 to 0.65 percent, depending on the type of business, on gross receipts of companies making more than $50 million, to be used for homelessness services. It would raise around $300 million, doubling the city’s homelessness budget.

The hundreds of millions of dollars raised could house 4,000 households, keep 7,000 people in their homes, and eliminate the wait list at homeless shelters, Jennifer Friedenbach, the executive director of the Coalition on Homelessness, which put forth the initiative, told me. She argues that large companies just got a 14 percent reduction in their corporate tax rate, and that the federal government is divesting funding in housing for poor people, so big companies “have a responsibility as corporate citizens to pay.” Though some companies have given to charity in the city, others have not, she said. “Charity is one time. Systemic change is forever,” she said.