In a letter sent Tuesday, 28 alders calling themselves the "Budget Accountability Coalition" said they will not vote for a budget that includes Johnson's proposed corporate head tax, his 33% increase to the personal property lease tax, or new spending.

"This version of your budget is a non-starter," the alders wrote. "This budget would hold back growth just when Chicago needs it most."

The mayor's office has estimated the two taxes would generate roughly $335 million a year. Johnson needs 26 votes to pass his budget, and with 28 alders already opposed, he must either win over critics or make significant concessions. The same coalition passed its own budget plan over the mayor's objections last year, making a reversal unlikely.

Johnson proposed the head tax, which he calls an "equitable employer tax," in his budget address last month despite advance warnings from a council majority that it would fail. The plan would charge companies with 125 or more full-time employees $25 per worker per month, with credits for employees working in designated Socioeconomically Disadvantaged Areas. The mayor's office estimates it would raise $101 million annually.

The lease tax proposal would raise the rate from 15% to 20% on leases of property, cloud computing services and digital software, while keeping car leases at 15% and cutting the rate for film production equipment to 11%. That change is projected to bring in $234 million.

Alders objected that the lease tax was already increased from 11% to 15% in the 2026 budget and was supposed to remain frozen at that level for two years.

"We gave Chicagoans our word on that rate. If we break it one year later, why should any Chicagoan believe the next commitment this Council makes?" they wrote.

Johnson responded with a letter to the full council saying his budget team is already working on unspecified changes to the SEED credits in the head tax plan and to the lease tax proposal. He did not commit to dropping either tax but said he is open to alternatives.

"I am appreciative of the specific ideas several members have offered for revenue solutions," Johnson wrote. "My office is carefully evaluating each proposal. I remain open to all concepts and look forward to reviewing more options as additional members have indicated that their teams are in the process of vetting solutions."

The council has also rejected Johnson's plan to use $75 million in parking meter deal proceeds to help cover pension payments in 2027. Alders voted 44-6 to use that money for an extra pension payment this year instead, blowing another hole in the budget.

Combined with the tax proposals most alders oppose, Johnson's plan is now more than $400 million short.

The council must pass a 2027 budget by the end of the year. Last year, Johnson's critics passed a budget on Dec. 20. The next full council meetings are scheduled for Dec. 8 and Dec. 9, though it is unclear whether a final budget vote will be ready by then.