$855M for infrastructure was the official ask, publically announced Sept 30, 2025.
Then also tax certainty in the form of a "PILOT" bill which is a mega-project bill that allows mega developments to negotiate a fixed long term payment with local taxing jurisdictions.
On the first point, the Bears have never publically stated with any real specificity what that $855M covers. But reading between lines I don't beleive it is even covering infrastructure for the whole development, just the stadium. But for some context, NY State and Erie counties $850m was a record setting contribution at the time of their agreement (not in % terms or inflation adjusted, but still). We can presume cost has only risen since then and will probably have creep beyond inflationary reasons. Ultimately it's evident to me is that the AH site was a bad investment because of how much infrastructure was needed, and I don't think it's unreasonable to question if the public benefit for infrastructure would be there (let alone being paid back with new tax revenue).
On the second point, I think the Bears have also been really bad at conveying specifics. There's been a lot of bad misinfo out there like "the state asked Bears to pay $200m". The state doesn't set tax rates/assessments, local taxing bodies do, and the $200m was never an ask from any government body but a third party think tank number on what the tax could be if the entire dev cost was the assessed value and taxed at standard commercial rate. And bad apples to apples comparisons are being made to much smaller properties, including Sofi where everyone is quoting as the highest stadium property tax ever at 8.8m, but that is additionally just the stadium and not entire 300 acre development. So at this point all we really know is Bears want new legislation, but even that wording they're still asking for tweaks on. And no explanation for why existing tax abatement structures like TIFs aren't suitable.