SAN FRANCISCO (CBS SF) — Tech companies in San Francisco have received millions of dollars in tax breaks for years, but now some city politicians want to make an exception to that rule.

The proposed ballot measure would come in the form a new payroll tax in San Francisco that large tech companies would have to pay.

READ MORE: Santa Clara Broncos Seeking Dream Ending: Back-To-Back College Cup Title On Home Field

Revenue raised from it would help fight the city’s two biggest problems: homelessness and the housing crunch.

From Yelp to AirBnB, tech companies have seen wild success in the past few years, and now the city they call home wants to cash in.

“It’s going after the large companies to pay their fair share,” said San Francisco Supervisor Eric Mar.

Mar is behind the ballot measure that would slap a 1.5 percent payroll tax on tech companies, but not the little fish.

His proposal focuses on tech companies with more than one million dollars in gross revenue.

“This is a way of assessing a fair share for these large tech companies that have benefited greatly from the city’s tax policies over the past five years,” explained Mar.

READ MORE: Gas Line Ruptured In American Canyon; Traffic Impacted

Mar announced the measure, which is co-sponsored by Supervisors Aaron Peskin and David Campos, Tuesday with the backing of community groups including San Francisco Rising, Jobs with Justice and the Coalition on Homelessness.

The city’s Mid-Market tax break lured tech companies like Uber and Twitter to the heart of San Francisco. But critics partly blame the influx of tech companies for the city’s housing crunch.

“This is in large part due to the tech boom that has left many of us out and left many of us fighting for our homes,” said Kung Feng of the organization Jobs with Justice SF.

A coalition of homeless and housing advocates is endorsing Mar’s tech tax. They’re banking on it bringing in big money — $120 million every year—for their causes.

“In order to truly address homelessness in SF, we need a sustainable revenue source,” said Jennifer Friedenbach of the Coalition on Homelessness. “And to do that we need funding.”

The handful of tech companies KPIX 5 reached out to either did not respond or said they had no comment.

Small businesses would also benefit from the tax.

MORE NEWS: Lake County Sheriff: Pilot Killed In Plane Crash In South Lakeport

As many as 75,000 would get their business registration fee cut in half, sweetening the pot to get the business community on board.