On Wednesday, Microsoft announced a commitment of $500 million “to advance affordable housing solutions” in the greater Seattle area. While it was striking for the company to acknowledge how supremely difficult it is for “lower- and middle-income workers to afford to live close to where they work,” 95 percent of its commitment would be in the form of loans to housing developers, much of it for market-rate housing that will benefit more-affluent residents.

What is needed in Seattle — as well as San Francisco; Austin, Tex.; New York City; Boulder, Colo.; and other urban areas where the rapid influx of high-paid tech workers has made housing unaffordable for nearly everyone else — isn’t a corporate takeover of housing policy but, rather, a per-employee “head tax” that would fund real investments in affordable housing, which should be a public good.

The notion of a head tax isn’t unprecedented, even in Seattle. In May 2018, faced with a crisis of homelessness and housing insecurity, the Seattle City Council levied a fee of $275 per employee on corporations whose annual revenues exceed $20 million — the most conspicuous of which is Amazon . (Microsoft is based in nearby Redmond, Wash.) The tax would have raised a modest but useful sum to build affordable housing units and fund social services. But just weeks later, after Amazon hinted that it might leave Seattle altogether, the Council voted overwhelmingly to reverse its decision.

It was a terrible loss for Seattle’s housing advocates, who were hoping for a systemic response to doubling rents, inhumanely fast evictions (Washington State has a three-day notice period) and a rise in the number of families living in their cars. And they were not reassured when, a few months after killing the head tax, Jeff Bezos, Amazon’s chief executive, announced that he would pay a minimum wage of $15 per hour to all of its United States workers , a boost to low-wage warehouse and cafeteria workers. But in Seattle, where the minimum wage is now $16 for big employers, low wages cannot buy decent housing. The average rent in Seattle was nearly $2,000 in 2017, and nearly half of all renters spent more than 30 percent of their incomes on housing. For many workers, $15 or even $20 an hour, at 40 or 50 hours a week, means couch-surfing.