U.S. municipal bonds issued by Chicago held up in light trading on Monday even as the city’s debt suffered another triple-notch ratings downgrade on mounting concerns about its public pension liabilities.

Late on Friday, Fitch Ratings cut its credit rating on Chicago’s $8 billion of taxable general obligation bonds to A-minus from AA-minus, citing the city’s lack of meaningful fixes for its underfunded city worker retirement system.

It also cut $497.3 million of Chicago’s sales tax bonds to A-minus, and $200 million of commercial paper notes to BBB-plus. The outlook is negative.

In one of a handful of small Chicago debt trades on Monday, some of the city’s 30-year unlimited general obligation bonds, due January 2040, opened lower at 92.6 cents on the dollar from 93.5 cents on Friday. But they recovered later on Monday, trading at 93.75 cents.

Other small blocks of Chicago bonds also traded at or near where they were trading on Friday. Trading was light for the Veteran’s Day holiday when most other sectors of the bond market were closed.

Fitch’s action brings its rating for Chicago’s debt in line with Moody’s Investors Service, which also chopped the city’s credit rating in July by three notches to A3.

The unfunded liability for Chicago’s four retirement funds had grown to $19.4 billion in 2012 from $11.9 billion in 2009, with a funded level of just 35 percent, according to Fitch rival Standard & Poor’s.

Fitch estimates that the funding ratio for the four plans is actually weaker still, at 32.9 percent, when a more conservative rate of return is assumed for the plans.

An 80 percent funded level is considered healthy.

Illinois lawmakers are struggling to solve the state’s own $100 billion unfunded pension crisis, forcing local pension problems to the sidelines.

But pension reform in the state “must include reform for municipalities such as Chicago,” said Chicago Mayor Rahm Emanuel in a statement through a spokesman to Reuters.

“The pension crisis in Illinois is not solved until relief is brought to Chicago and all of the other local governments across our state that are standing on the brink of a fiscal cliff because of our pension liabilities,” he said.

(Reporting by Hilary Russ; Editing by Dan Burns and Leslie Gevirtz)