Foxconn was promised tax credits, with the requirement that they meet certain job creation and investment targets. Tax credits lower your tax owed dollar for dollar. What happens when the credits exceed the taxes due? I looked it up:

The contract[1] states that these are tax credits pursuant to Wisconsin State statute 71.28(3wm)[2], which states "If the allowable amount of the claim under this subsection exceeds the taxes otherwise due on the claimant's income under s. 71.23, the amount of the claim that is not used to offset those taxes shall be certified by the department of revenue to the department of administration for payment by check, share draft, or other draft[...]"

So if Foxconn meets the investment and job creation requirements and doesn't have significant state tax burdens, the Wisconsin tax payers will have to write big fat checks to Foxconn, hoping that the indirect economic impact of Foxconn's activity is enough to offset these payments. In that case, these subsidies are a direct cost.

[1] https://wisconnvalley.wi.gov/Documents/WEDCcontract-state.pd... [2] https://docs.legis.wisconsin.gov/statutes/statutes/71/IV/28