BOISE — September state general fund revenues for Idaho came in nearly $50 million over forecasts, further bumping up the state’s record billion-dollar budget surplus.

September’s revenues of $459.1 million were 12.2%, or $49.9 million, higher than forecast, and 20.4% higher than revenues for the same month a year earlier as the state’s economy continued to outperform.

Both income taxes and sales taxes beat forecasts for the month, with corporate income taxes coming in 29.3%, or $17.9 million, ahead of forecast; individual income taxes ahead by 8.2%, or $12.8 million; and sales tax revenues 10.3% over forecasts. That put sales tax collections in September at $187.6 million, $17.5 million ahead of forecasts.

Idaho’s state tax revenues have exceeded forecasts every month since the fiscal year started July 1.

State economists Greg Piepmeyer and Saruul Khesar didn’t speculate in their monthly General Fund Revenue Report on the reasons for the unexpectedly strong revenues, which give the governor and Legislature even more options to consider when they convene in January and begin setting the budget for the next state fiscal year.

When the Legislature finished its regular session in May, it had left $139.5 million unspent and unbudgeted, as an anticipated ending balance for the fiscal year. That figure had increased by $754.9 million in unanticipated tax revenues by June 30, bringing it to a total of $894.4 million. July added another $38.8 million in unanticipated general fund tax revenues, bringing the tally to $936.2 million. August’s extra revenues bumped the tally up to $983.1 million; and September’s have now pushed it to $1.033 billion.

And as of July 1, a new revenue forecast kicked in, reflecting another $513 million in state general fund revenue anticipated over the current fiscal year, 2022, compared to the forecast used by lawmakers to set the state’s budget for the year. Add that in, and the projected year-end balance at the end of the current fiscal year next summer rises to well over $1.5 billion.

That’s more than the state’s entire general fund budget was in 1998.

In the Legislature’s July General Fund Budget Monitor Report, analyst Keith Bybee wrote, “This extraordinary estimated ending balance is driven by a large one-time cash balance carried over from fiscal year 2021 and the ongoing revenues.” But he noted that balance will change over time based on monthly revenue collections, another revised revenue forecast that’s due in January, and any mid-year budget adjustments or legislative actions.