Why US tech giants are putting billions into housing

History teacher Leon Sultan was raised in a San Francisco that working class families could call home. That place has, for the most part, vanished.

The city is now the centre of America's thriving tech industry, with some of the highest housing costs in the US. Homeownership is in retreat and homelessness is surging, alongside newly-minted fortunes.

Mr Sultan currently lives in a rent-stabilised one bedroom apartment with his wife, who also works in education, and his four-year-old son. When they move to a bigger place in a few weeks, their rent will almost double.

"When I was born in the city in 1978, a two-income earning family could buy a home," he says. "At this point, the only way to buy a home, if you're a normal person... is to have some sort of edge."

"I feel lucky that I haven't been displaced yet."

Mr Sultan, and many others, blame the changes on the Bay Area's tech boom, which has created vast wealth divides.

The growing backlash has played out in fights over new taxes targeting tech and protests against the commuter buses that ferry workers south from San Francisco to Silicon Valley, where many tech giants have their headquarters.

For years, the tech giants have faced down their critics unabashed. But now there are signs of change.

In June, Google said it would invest $1bn in housing and Facebook has also pledged $1bn. Apple upped the ante this month, saying it would devote $2.5bn to the issue.

"We know the course we are on is unsustainable," Apple boss Tim Cook said as he revealed his firm's plans.

Those moves followed a flurry of smaller donations and activity from firms such as Cisco and Microsoft, which said it would invest $500m in housing in its home state of Washington.

The commitments represent a "kind of acknowledgement from the tech industry that yes, they're playing a role in this housing affordability crisis," says Jeffrey Buchanan from Silicon Valley Rising, which has pressed the tech giants on the issue for years.

"I'm hopeful that it is a change in mindset in the industry... the old way doesn't work."

As the tech industry has boomed, home prices and asking rents in the Bay Area have roughly doubled over the past decade, becoming by many counts the highest in the US.

Last month, the San Francisco Association of Realtors said the median home price in San Francisco had hit $1.4m. The average asking rent exceeded $3,200 per month, according to research firm Moody's Analytics-Reis.

Wages in the area have increased as well, but not as fast as housing costs.

A family needs to earn $126,800 a year to rent a typical two-bedroom property in San Francisco without spending more than 30% of their income - the share typically considered affordable. In 2017, about 40% of Bay Area renters spent more.

For Mr Sultan, homeownership is out of the question, but he says his family is lucky. There's a woman on his street living in her car.

"I'm not feeling sorry for myself," he says. "There are a lot of folks in this city who are struggling way harder than we are."

The high costs are forcing companies to pay more and work harder to find staff, one reason the tech firms have taken an interest.

For the most part, their pledges aren't philanthropy.

Apple is lending the state up to $1bn to help finance affordable housing projects and providing $1bn to California's first-time homebuyer fund.

Google and Facebook also plan to invest hundreds of millions in new housing. Land owned by the tech companies that will be made available for housing construction accounts for another major part of the commitments - a full $750m worth in Google's case.

Such large promises are "unprecedented", but a lack of detail makes them hard to evaluate, says Carol Galante, director of the Terner Center for Housing Innovation at the University of California, Berkeley.

"It's in their self-interest but it's also obviously in the community's interest."

Facebook and Google have each said their plans should produce about 20,000 new housing units, some of which will be offered at below market rates. Apple has not provided an estimate for its total commitment, but expects to build about 3,600 new affordable units on its land.

But California State Senator Scott Wiener, whose district includes San Francisco, says the plans represent "a drop in the bucket" compared to the money and policy changes needed.

"I'm glad that Apple, Facebook, Google are doing this, but I think we also have to be crystal clear that this is not going to solve the problem."

Between 2012 and 2017, San Francisco added fewer than 21,000 new housing units, while the population grew by more than 58,000 and the number of jobs jumped by 130,000.

Senator Wiener blames policies that hamper development - like rules that limit the height of buildings - for much of the growing gap between supply and demand.

"The problem is not that we have job growth," he says. "The problem is we didn't plan for it."

But Peter Cohen, from the Council of Community Housing Organisations, says it's "simplistic" to rely on increased supply to solve the crisis.

New construction is often designed for the tech industry's upper crust, even though many of the new jobs are lower-wage ones such as cooks and drivers, he says.

He says the tech industry's announcements seem in part like a "branding" effort to pre-empt new policies, such as higher taxes.

"We've got to have stable and significant sources of funding," he says. "Otherwise we're just chipping around the edges."

Mr Sultan, the teacher, says he welcomes the plans for more housing - especially if it's close to company campuses. Expansion in other regions such as Texas - where Apple has announced a new base - make him even more excited.

"The big issue for me is, why does the tech industry have to be housed in San Francisco," he says. "Why can't they disperse throughout the country?"

But the broad trends seen in his home city - rising housing costs, slow construction, and declining homeownership, especially among younger families - are happening across the US, especially in areas where tech companies are expanding.

And as people and companies leave the Bay Area, they add to housing strains in suburbs and other cities, pushing the poorest further away from the jobs they need.

"We've got this kind of rolling musical chairs that's going on," Ms Galante says. And those with the least, she warns, are "losing".