Analysts at the three major rating agencies, which rate Illinois one or two notches above junk, declined to comment on the timing of their decisions.
With the help of some Republican votes, the Democratic-controlled Illinois Legislature last Thursday overrode Republican Governor Bruce Rauner's vetoes and enacted a $36 billion fiscal 2018 budget and a $5 billion income tax increase.
The action ended an unprecedented two-year budget impasse that ballooned the state's unpaid bill backlog to about $15 billion.
Illinois State Treasurer Michael Frerichs, a Democrat, on Monday unveiled a five-step plan to avoid a junk rating that included Rauner taking steps to issue up to $6 billion of bonds the legislature authorized to begin paying off bills. He also recommended the governor visit credit rating agencies to assure them he intends to implement the budget package.
A junk rating would make future bond sales more difficult and expensive.