Veritas Investments, one of San Francisco’s biggest property owners, is looking to sell 76 of its apartment buildings, and San Francisco officials are joining tenant advocacy groups seeking to turn some of them into permanent affordable housing.

On Monday, Supervisor Dean Preston is expected to call on Veritas to pause its efforts to sell the buildings on the private market for 60 days so that city officials can consider whether any can be added to affordable housing stock. Preston also wants to ensure that tenants in Veritas buildings offered for sale are afforded protections against displacement.

The buildings represent nearly 30% of Veritas’ total portfolio in San Francisco and were put up for sale in late December.

Veritas first offered the buildings to a group of nonprofit housing organizations under San Francisco’s Community Opportunity to Purchase Act, a law meant to create and preserve affordable housing in the city. The company said it received initial interest from three organizations — the Tenderloin Neighborhood Development Corp., the Chinatown Community Development Center and the Mission Economic Development Agency.

The organizations cumulatively expressed interest in 16 buildings, but Justin Sato, Veritas’ chief strategy and portfolio officer, said none made it much further than that. Nonprofit housing groups have 30 days to decide whether to purchase a multifamily building that’s up for sale, but that time passed, and Veritas was ready to seek bids from other buyers.

“In our view, we really allowed them the proper window of time to evaluate the opportunities to see which properties might be a good fit for conversion to affordable housing,” Sato said. After fielding some requests for information about the properties, “we didn’t hear any kind of response.”

But in an interview Friday, Preston said 30 days isn’t enough time to properly vet a housing portfolio that includes more than 2,100 individual units, many of which are rent-controlled.

It’s possible, though far from certain, that an agency such as the Mayor’s Office of Housing and Community Development could help finance a nonprofit group’s acquisition of some of the buildings. Veritas has sold two of its apartment buildings to nonprofits. One at 270 Turk St. was sold to Tenderloin Neighborhood Development Corp. The other, at 305 San Carlos St., was sold to the the Mission Economic Development Agency.

“I don’t think any of our laws contemplate a 76-building portfolio being plopped on the market all at once,” Preston said, particularly around the holidays.

“The stakes are high enough with a portfolio of that size of rent-controlled units to warrant having a period of time where city leaders and tenant leaders and Veritas can hopefully sit down and talk about this portfolio in depth and how tenants can be protected.”

As of Friday afternoon, Preston said he had not contacted Veritas, but that he expects to by Monday.

Sato said Veritas is open to further discussions with the city and nonprofit groups about potential sales.

“We’re always willing to work with the city around any potential interest in acquiring our buildings,” he said.

Veritas has had a fraught history for years in San Francisco. City officials and tenant organizers have routinely lambasted the company as an example of the ills brought on by corporate landlords. In 2018, a group of 68 Veritas tenants sued the company, saying its long-term tenants had endured systemic harassment — such as drawn-out construction work — meant to drive them from their homes so they could be replaced by new tenants paying substantially higher rents. Veritas has denied those claims and said the company had begun a “hardship program” in recent months to protect its most vulnerable residents.

“We can’t lose this opportunity to protect such a large amount of working-class tenants in San Francisco,” said Sarah Sherburn-Zimmer, executive director of the Housing Rights Committee of San Francisco. “We can’t lose a single unit in San Francisco, and we have to do whatever it takes to protect them.”

The group, a vocal Veritas critic for years, has called on the company to pause its private-market sales and has organized tenants so they’re aware of their rights in the event of a sale.

The committee posted a list of addresses of the buildings being sold to its Facebook page on Jan. 20, in a move that could present a potential confidentiality breach. During a potential sale of a multifamily building, the city’s Community Opportunity to Purchase Act requires that certain information, including building addresses, be kept under wraps while nonprofit groups explore a deal.

Sherburn-Zimmer declined to say where the group got the information but said it was posted so that Veritas tenants could find out whether their building is for sale.

“There is no violation that I know of in how I got the information,” she said. “I think it’s crucial that tenants have the right to protect themselves.”

Dominic Fracassa is a San Francisco Chronicle staff writer. Email: dfracassa@sfchronicle.com Twitter: @dominicfracassa