Boston Mayor Michelle Wu’s tax shift bill was killed again in the state Senate, this time as an amendment to alternative Senate-led property tax shock legislation that was overwhelmingly defeated by the chamber on Thursday.

The Senate voted, 33-5, to defeat an amendment filed by state Sen. Michael Rush, a Boston Democrat, that closely mirrors the language included in a home rule petition the mayor has been pushing for nearly two years that would shift more of the city’s tax burden from the residential to commercial sector.

The mayor’s legislation was killed by the state Senate in late 2024, and stalled in that chamber again all last year. It was not taken up again until Thursday. Wu renewed her push for Senate approval last month while portraying her plan as critical to lower the projected 13% tax hike for homeowners that the city says is driven by a 6% drop in commercial values alongside a 2% rise in residential values.

The day’s vote on Rush’s nearly identical amendment, filed at the request of the mayor, leaves the future of Wu’s proposal uncertain, given that it appears to have no path forward in the Senate, despite clearing its two other legislative hurdles — the Boston City Council and state House of Representatives — three times.

“I hope we can move on past this issue to work with our municipal partners on all the goals we truly share,” said state Sen. William Brownsberger, a Belmont Democrat who represents parts of Boston and filed the tax shock bill Rush was seeking to amend with the mayor’s home rule language.

Wu’s office did not respond directly to an inquiry about whether the mayor plans to continue pursuing her legislation, which seeks to exceed the 175% state limit for shifting taxes onto commercial properties in order to lower residential tax increases, for three years.

Her office, however, pointed to the support the amendment received from four of six Boston senators, while suggesting that the mayor’s proposal has widespread support in the city.

“In addition to having overwhelming support from the people of Boston, the city’s residential tax relief legislation has had support from 12 of 13 Boston city councilors, all 16 Boston state representatives, and now four of Boston’s six state senators,” a city spokesperson said in a statement.

“We’re grateful to Senator Rush for putting this amendment forward, and Senators Lydia Edwards, Liz Miranda, Sal DiDomenico and Patricia Jehlen who voted for this today,” the mayor’s office added.

Brownsberger and state Sen. Nick Collins, a South Boston Democrat, were the two Boston senators to vote against the Rush amendment, after having co-led the push to kill the mayor’s tax shift bill in the Senate in late 2024.

The Senate approved Brownsberger’s alternative tax relief bill, by a 37-1 vote.

His “tax shock” legislation would give “cities and towns the ability to shield their most vulnerable taxpayers from the shock of an extraordinarily high tax bill” in years when residential property tax hikes are expected to exceed 10%, per a Senate fact sheet.

Brownsberger’s bill would phase in increases or offer targeted tax credits in years with projected double-digit tax hikes.

Co-sponsored by Collins and Senate Minority Leader Bruce Tarr, a Gloucester Republican, the tax shock bill now moves on to the House of Representatives for consideration.

“This is a targeted relief measure,” Brownsberger said of his bill. “It’s only helpful to municipalities in a tax shock year. Tax shock years are not common, fortunately … and if a city has reserves, it can work.”

By comparison, Brownsberger said the mayor’s plan, by way of Rush’s failed amendment, does not target tax relief to the most vulnerable homeowners. He said wealthy homeowners would likely see lower tax bills with the tax shift while small business owners would be hit with higher property taxes.

Brownsberger added that the language in Rush’s amendment would have opened up the floodgates for all cities and towns to tax commercial properties beyond the 175% maximum shift allowed under state law to lower residential tax bills.

“The whole fundamental compromise of (tax) classification would be out the door, and I don’t believe that’s good for the Commonwealth in the long run,” Brownsberger said.

State Sen. Lydia Edwards, an East Boston Democrat who voted in favor of the Rush amendment, said the city’s residents are most concerned right now about taxes, and the tax shift language would help ensure housing stability.

She questioned why the Senate was unwilling to trust the City of Boston’s assessment that the tax shift was needed to stabilize residential taxes, when it was willing, “on so many different occasions,” to trust Boston’s ability to “manage itself and to manage its zoning and to manage its fiscal responsibility” with prior home rule petition approvals.

“Why don’t you trust the Boston assessing department when it says I need this tax shift to protect my residents?” Edwards said. “Just be consistent.”