Unofficial vote results in San Francisco on election night showed strong support for a parcel tax measure backed by Mayor Daniel Lurie and a bevy of labor unions that is designed to generate funding for public transit.

Proposition H was headed toward likely victory, with about 72% of votes cast in favor. It would raise about $160 million a year for public transit and comes in addition to a regional sales tax measure that would be divided among several agencies.

Prop H would dedicate its funding entirely to the San Francisco Municipal Transportation Agency, which is facing a bleak financial outlook in coming years, due in part to a steep reduction in Muni ridership during and after the COVID-19 pandemic.

The measure needs a simple majority to pass, thanks in part to a signature-gathering campaign Lurie launched in March to qualify it for the ballot through a citizen-led initiative. Had Lurie sought approval from the county Board of Supervisors to qualify the measure, it would have needed two-thirds’ approval to pass.

Early returns indicated that would not have been a problem for voters, who appear eager to pass the measure to shore up Muni’s desperate financial outlook.

If the results hold, the measure will impose a value-based property tax, known as an ad valorem tax, of various amounts, depending on property type and value.

Most homeowners would see an increase of about $129 a year. Those would be single-family residential properties under 3,000 square feet, which would cover about 95% of residential properties in the city, according to the campaign’s backers.

About $65 per year could be passed on to renters.

Top funders for the campaign, dubbed “Stronger Muni for All,” included OpenAI, Anthropic and Ripple Labs, which donated $500,000 each, according to its website.

It was also supported by several labor unions, including local Teamsters and Service Employees International Union chapters, along with eight members of the county Board of Supervisors.

Mixed-use parcels up to 5,000 square feet would pay $799 more a year under the increase. The largest commercial property owners would pay up to $400,000 more a year, according to the campaign.

Muni is facing projected deficits of over $300 million in coming budget years.