The Illinois Teachers Retirement System (TRS) voted on Friday to reduce its anticipated rate of return on investments. The move means Illinois will have to pay $421 million more next year into the pension fund.
The Rauner administration, which sought to postpone the vote, stressed that the TRS change could have a "devastating impact" on the state.
For its part, TRS lowered its expected rate in order to safeguard benefit payments.
"No one should think we're being insensitive," said TRS Executive Director Dick Ingram. "But what's been devastating is seven years of underfunding."