Chicago’s Aon Center Is Appraised at $195 Million

One of Chicago’s most recognizable skyscrapers has become one of the largest troubled office assets in the US. Aon Center was appraised at $195 million in May 2026, its $536 million mortgage was not repaid at its modified July maturity, and the owner’s request for another three-year extension was rejected. The tower illustrates how the US office downturn is moving from elevated vacancy into losses for lenders and bond investors.

Aon Center faces another debt restructuring

Aon Center stands at 200 East Randolph Street next to Millennium Park. Completed in 1973 as the headquarters of Standard Oil of Indiana, the tower rises 346 meters and has 83 above-ground floors. It is now Chicago’s fourth-tallest skyscraper after Willis Tower, Trump International Hotel & Tower and St. Regis Chicago.

601W Companies bought the building from Piedmont Office Realty Trust for $712 million in 2015, or about $260 per square foot. The approximately 2.7 million-square-foot tower was about 87% leased when the deal closed, with tenants including Aon, KPMG, Microsoft, JLL and Kraft Heinz.

The building has since become one of the most visible examples of US office distress. Bloomberg notes that the problem extends beyond the owner because the mortgage was distributed across several commercial mortgage-backed securities transactions, leaving bond investors exposed to the eventual recovery value of the property.

The appraisal has fallen to $195 million

When Aon Center was refinanced in 2018, the capital structure included a $536 million mortgage loan and two mezzanine loans totaling $141.5 million. Combined financing therefore reached $677.5 million.

The securitization documents contained two property valuations. The “as-is” appraisal was $780 million. A separate $824 million hypothetical appraisal assumed, among other things, completion of amenity-floor work and excluded certain leasing costs associated with recently signed tenants. Occupancy at origination was 87.9%.

A new appraisal completed in May 2026 valued the building at $195 million. The property is therefore worth substantially less than the $536 million mortgage alone, making a straightforward refinancing of the existing balance difficult without new equity, a reduction in debt or another restructuring.

The owner already received one extension

The 2018 mortgage originally matured on July 1, 2023. The borrower received a three-year modification that extended the maturity to July 2026.

Conditions at the building deteriorated during that period. The loan returned to special servicing in February 2026 after the borrower failed to make a required payment into a reserve for tenant improvements and leasing commissions. The latest occupancy figure available at that point was about 66%, down from roughly 88% at loan origination. The property’s 2024 net cash flow was 12% below 2023 and almost 30% below the level recorded when the loan was issued.

The loan was not repaid at its modified July 2026 maturity. The borrower sought another three-year extension, but the special servicer rejected the request. KBRA reported that the parties were instead negotiating a forbearance agreement of up to two years that would require substantial upfront and continuing capital contributions to rebuild leasing reserves.

Major tenant risk has not disappeared

Aon Center’s outlook also depends on whether it can retain its largest occupiers.

JLL has been considering whether to move its global headquarters from Aon Center to another downtown Chicago property. Its current lease runs until May 2032, although it has an option that could allow an earlier departure. JLL had already listed more than 61,000 square feet of its Aon Center space for sublease in 2023. No final relocation decision has been announced.

For lenders, that uncertainty matters. Once property value has fallen below outstanding debt, the loss of a major tenant can reduce income further while forcing the landlord to spend heavily on renovations, leasing commissions and incentives for replacement tenants.

Downtown Chicago vacancy remains high

Aon Center’s problems are unfolding within one of the most challenged major office markets in the US.

Direct vacancy in Chicago’s central business district reached 26.8% in the second quarter of 2026, compared with 26.7% three months earlier. Year-to-date net absorption was negative by about 500,000 square feet.

Leasing activity nevertheless showed some improvement. Transactions larger than 10,000 square feet totaled 1.5 million square feet during the quarter. No office projects were under construction, limiting future additions of new top-tier space. Six major downtown office sales closed during the quarter, including 500 West Monroe, which traded at an estimated 76% discount to its previous sale price.

Those transactions are helping reset comparable values for lenders and appraisers. Lower prices for nearby properties make it harder for owners to support valuations established when borrowing costs were lower and office demand was stronger.

Demand is concentrating in the best buildings

High downtown vacancy does not mean every part of Chicago’s office market is equally weak. Companies continue to sign leases, but demand has increasingly concentrated in newer towers and extensively renovated properties.

That creates a costly problem for older skyscrapers. Landlords often need to finance tenant improvements, offer free-rent periods and pay significant leasing commissions to compete for large occupiers.

Aon Center has undergone substantial upgrades, but its age remains relevant. The building is more than 50 years old and competes for tenants with newer office stock in other parts of downtown Chicago.

Office distress is reaching bond investors

For several years, the US office downturn was measured mainly through vacant floors and falling appraisals. Credit data now show the consequences moving deeper into the financial system.

The US office CMBS delinquency rate reached 12% in August 2026. The office special-servicing rate rose to 16.9%. Across all commercial-property types, the delinquency rate was 7.85% and the special-servicing rate reached 11.42%, the highest since February 2013. Loans reaching maturity without repayment were the main source of new distress.

Aon Center fits that pattern. The property remains operating and collecting rent, but the original debt balance no longer matches the building’s current valuation or today’s financing conditions.

Tens of billions of office debt are reaching maturity

Bloomberg estimates that about $64 billion of office CMBS debt is scheduled to mature in 2026 and 2027. Nearly $40 billion is already delinquent, in default or on lender watchlists.

Chicago carries a particularly concentrated exposure. Of almost $1.7 billion in office CMBS loans scheduled to mature in the city during 2026, roughly $1.45 billion was already delinquent.

This marks a different stage of the office correction. A borrower can continue paying interest and operating a building for years, but once the principal reaches maturity it must either find a new lender, contribute fresh equity or persuade existing creditors to accept a restructuring.

Aon Center shows the scale of office repricing

The central question for Aon Center is no longer whether it remains a Chicago landmark. Its architectural significance has not changed. The financial assumptions behind its ownership have.

In 2018, the property supported $677.5 million of mortgage and mezzanine financing. The latest appraisal is now well below the mortgage balance alone.

That makes the current negotiations between 601W and its creditors fundamentally a discussion about how the loss will be allocated. The lower the eventual value of the tower and the more capital required to secure new leases, the harder it becomes to recover the existing debt in full.

As International Investment experts report, Aon Center illustrates a new stage of the US office downturn. Elevated vacancy is no longer the only issue: legacy loans are reaching maturity at a time when current property values cannot support replacement financing of similar size. Falling prices may create opportunities for investors to acquire high-quality buildings at substantial discounts to previous valuations, but the purchase price is only part of the equation. Capital required for renovations, tenant incentives and future leasing can determine whether an apparently cheap office asset is actually an attractive investment.

FAQ: Aon Center and Chicago’s Office Market

How much is Aon Center worth now?

The latest reported appraisal, completed in May 2026, values the property at $195 million.

How much was Aon Center worth previously?

601W Companies bought the tower for $712 million in 2015. At the 2018 refinancing, its as-is appraisal was $780 million, while a hypothetical appraisal based on additional assumptions was $824 million.

How much debt is tied to Aon Center?

The mortgage loan totals $536 million. When the 2018 financing was arranged, the capital structure also included $141.5 million of mezzanine debt.

Why was the loan not repaid in 2023?

The borrower obtained a three-year modification in 2023, moving the maturity date to July 2026. The loan was not repaid at the extended maturity.

What is happening with the loan now?

The borrower’s request for another three-year extension was rejected. The parties have been negotiating a shorter forbearance agreement that would require additional owner capital.

What is Aon Center’s occupancy?

The latest published figure was approximately 66%, compared with roughly 88% when the mortgage was originated in 2018.

What is CMBS?

Commercial mortgage-backed securities are bonds backed by loans on office buildings, hotels, shopping centers and other commercial properties. Payments on the underlying loans are used to repay investors.