Dating as far back as 1917, reports by the Illinois legislature described the condition of the state and municipal pension systems as "one of insolvency" and "moving toward crisis".[8] Such findings continued in the 1940s to 1960s, when the state pension commission warned of the pension systems' impending insolvency and the growth of unfunded pension liabilities, noting the appropriations were "grossly insufficient" and "below mandatory statutory requirements."[8]
Throughout the 1970s, the funding of the state's pension systems rose from roughly 35% to 50%. From the 1980s to the mid-1990s, pension funding levels fluctuated between 50% and 60%.[8][9]
In 1994, when unfunded pension liabilities hit a then-high of $17B, new legislation was passed under governor Jim Edgar to raise the funding ratio from 52% to 90% by 2045, referred to as the 'Edgar Ramp'. However, a later complaint by the Securities and Exchange Commission noted even at the levels proposed by the reform package, unfunded pension liabilities would continue to grow.[10] While the state's pension funding ratio increased to 75% by 2000, the funding improvements were driven by $15B of favorable changes to actuarial assumptions and better-than-expected investment returns, and state contributions fell $6B short of required amounts.[9]
From 2001 to 2003, following the dot-com crash, poor investment returns contributed to an increase in unfunded liabilities, representing $14B of the $27B rise.[9] By 2003, the unfunded liability reached $43.1B.[2] In 2003, the state sold $10 billion in pension obligation bonds used to reduce unfunded liabilities for fiscal year 2003 ($2.2B) and 2004 ($7.3B).[11]
In 2005, Senate Bill 27 allowed for reduced contributions in times of budgetary pressure, known as 'pension holidays'. In 2006 and 2007, contributions were roughly $1B lower than the amounts required under the 1995 legislation.[11][12]
Poor investment returns caused by the 2008 financial crisis, combined with insufficient contributions, increased the unfunded liability from $42B in 2007 to $86B in 2010.[2] In 2009, Governor Pat Quinn included pension reforms for newly-hired public employees, including a higher retirement age and capped cost-of-living adjustment rate, but the proposed changes were not enacted by lawmakers.[13][14]
In 2013, Illinois passed a pension reform bill which reduced retiree cost of living increases, raised retirement ages, limited pensionable salary, lowered the amounts current employees contribute, set up voluntary 401(k)s and guaranteed the state makes contributions on time.[15][16] Legislators estimated the reform would save roughly $160 billion over three decades.[15] In May 2015, the Illinois Supreme Court unanimously overturned the law on the grounds that it violated the benefit protection clause in the Illinois Constitution (Article XIII, Section V) which states
"Membership in any pension or retirement system of the State, any unit of local government or school district, or any agency or instrumentality thereof, shall be an enforceable contractual relationship, the benefits of which shall not be diminished or impaired."[17]