With her proposal to address the impending increase stalled in the Senate, Boston Mayor Michelle Wu's office said city residents' taxes could increase 28 percent — a large quarterly jump but less than originally estimated — unless senators on Beacon Hill act her proposal to shift more of the city's tax burden onto businesses by late November.

"It affirms that this tool is needed, and this is the direction that we are seeing valuations change," Wu said at a media briefing Wednesday morning organized by her office, held to announce the first assessment estimates and to continue to push for the property tax shift.

The mayor originally predicted residential property taxpayers could see as much as a 33 percent increase in their taxes come January, as commercial properties have seen a reduction in taxable value as fewer companies have returned to downtown offices in the wake of COVID-19. About 60 percent of Boston's property tax revenue comes from commercial property taxes.

The Wu administration wants to get approval for the tax change before it has to send tax bills out to residents — and time is ticking. The House has already gotten behind the idea, but it needs approval from the Senate and the governor. Wu said it will need to be done by late November to prevent Boston residents from getting a bill that includes the 28 percent hike.

Wu met with Senate President Karen Spilka and members of the Senate's Boston delegation last month.

Asked about that meeting Wednesday, the mayor said she's "answering as many questions as possible for anyone who needs more information."

"If there's a way to improve this process that makes it feel more predictable or accommodating to the business community, while also protecting residents, we are all for making those kinds of changes," Wu said.

She highlighted one piece of the bill, a so-called "trigger window." Wu said the home rule petition had language that allowed a three-year window for the city to start the clock on the tax shift at any time, as they did not know when the property valuations would shift significantly.

"We're now sure that we would need it this year. So [we're] very much willing to, for example, remove that language or be clear for predictability that it would be used this year, and not subject to, sort of, any time within the next three years," Wu said.

She did not directly answer a question about whether she had been in touch with Gov. Maura Healey about the proposal, or has the governor's support. Healey's signature is the final hurdle the proposal would need to clear to go into effect.

"Those are the types of conversations we're having at every level," Wu said.