Beacon Hill spent most of the past year in hand-wringing mode over the state's finances as tax revenues sagged month after month and new costs exploded, but lawmakers might soon have hundreds of millions of dollars in extra cash available for education and transportation.

Massachusetts has collected about $1.8 billion from a voter-approved surtax on the state's highest earners through the first nine months of the fiscal year, the Department of Revenue said Monday in a quarterly report.

That's more than $800 million more than what the Legislature and Gov. Maura Healey planned to spend in surtax revenue for all of fiscal year 2024, raising the possibility of a sizable pot that will land in an Education and Transportation Reserve Fund and the Education and Transportation Innovation and Capital Fund, both surtax-specific accounts, once the books close.

Senate budget chief Michael Rodrigues said he looks forward to “discussion next year when the time comes” about how lawmakers should divvy up above-expectation surtax collections, which must be used on education and transportation needs under the constitutional amendment that voters approved in 2022.

“We're not going to know for sure until the comptroller determines it in December, but we are on track to see excess 'Fair Share' revenues in the $800 [million] to $1 billion range,” Rodrigues said during remarks on the fiscal 2025 budget on the Senate floor. “Those dollars, as I said earlier, will be statutorily deposited into a reserve fund for use by all of us to appropriate at a future time into one-time capital investments into education and transportation.”

“We will not have any problems identifying those,” he added. “As we all know, those are two areas of immense need.”

The latest DOR quarterly surtax report -- which Rodrigues described during Senate proceedings as something “literally hot off the press” -- represents welcome news for Beacon Hill budget-writers who had been feeling the heat for months.

State tax collections lagged behind projections for most of fiscal year 2024, even after Healey implemented new controls that included the first mid-year spending cuts since 2016. The tax haul in April then beat expectations by a wide margin, providing a new jolt of optimism even as officials warned that the tax dollars might not translate one-to-one into the annual state budget.

Now, DOR's third-quarter report gives an even clearer indication that Beacon Hill is bringing in far more money from the voter-approved 4 percent surtax on personal income above $1 million than the agreed-upon estimate, which Rodrigues described as “very conservative.”

“This is exciting because it's the first concrete numbers we have seen showing that 'Fair Share' revenue is coming in far above the initial projections,” said Andrew Farnitano, a spokesperson for the Raise Up Massachusetts campaign that spent years pushing for the surtax. “These numbers show that the commonwealth collected nearly $2 billion in that year already, with a few months to go. What that means is there will be even more money available to spend on the critical transportation and public education needs that Massachusetts has.”

Better-than-budgeted surtax collections would not work the same way as a more traditional tax revenue surplus.

Under a framework built into the fiscal 2024 state budget, any surtax revenues above the budgeted threshold get split between two destinations. Fifteen percent of the overage is deposited into a savings account, set aside to maintain investments if surtax collections drop down the line, and the other 85 percent goes into an “Education and Transportation Innovation and Capital Fund.”

Money in that latter fund must be spent on one-time investments “including, but not limited to, pay-go capital” or one-time projects “related to quality public education and affordable public colleges and universities and for the repair and maintenance of roads, bridges and public transportation,” as the Massachusetts Taxpayers Foundation laid out last year.

If fiscal year 2024 ends with $1.839 billion in total surtax collections -- a figure that could change in the final three months of the cycle -- about $125 million would go to the reserve savings fund and $713 million would become available for one-time projects.

Unlike traditional budget surpluses, which must be allocated in a timely way, there's no ticking clock attached to excess surtax collections, and it's not clear when or how lawmakers would move to carve up the funding.

“I'm happy to learn it looks like we are going to have significant dollars in order to make investments in much-needed capital for both education and transportation,” Rodrigues said. “I look forward to that discussion next year when the time comes.”

Beacon Hill will have plenty of options for a supplemental surtax spending spree, and education and transportation advocates are likely to roll out their pitches early. The MBTA, for example, is facing a massive operating budget gap in the coming years, and its leaders estimate it would cost nearly $25 billion to repair all parts of the system not in a state of good repair.

In 2022, voters approved the surtax, which was supported by Gov. Maura Healey, by a margin of 52.3 percent to 47.7 percent after years of effort by a coalition of labor groups, educators and other advocates.

Opponents contend that the higher tax rate on income above $1 million will push wealthy residents to other states, chipping away at the tax base.

“Whatever short term financial benefit the state will receive from the income surtax will be outweighed by the long term negative effect this tax is having on the state,” said Paul Craney, a spokesperson for the right-leaning Massachusetts Fiscal Alliance. “It's chasing out high income earners and making the decision very easy for taxpayers who are regularly impacted by this tax to domicile in more tax friendly states.”

Lawmakers and the Healey administration expect to have about $1.3 billion in surtax revenue -- less than the state collected in the first nine months of fiscal 2024 -- to use in the entire fiscal 2025 budget.

In fact, their surtax forecast stands in contrast to all other tax collections, which they expect to decline.

“We are in unusual times where we see the state revenue collections are on a roller coaster,” Senate Minority Leader Bruce Tarr told reporters Monday.

Senators introduced their version of the $57.9 billion spending plan Monday. Rodrigues said the last two months of state revenue collections suggest “our fiscal situation might be stabilizing.”

“It's still a rocky road,” the Westport Democrat said, soon adding, “But I am confident that we have finally figured out the new normal of where we are building our FY25 budget off of and we will build future budget bills off in the future.”