Blackstone has bought an iconic Chicago office tower.

The investment manager said it has bought the Willis Tower from its holding company, 233 South Wacker, for an undisclosed amount.

Blackstone bought the building for its Real Estate Partners VII fund.

Separate media reports said Blackstone has paid around $1.3bn for the asset, formerly known as the Sears Tower.

The 3.8m sqft office building is the second-tallest office building in the US and the fifth-tallest office building in the world.

Jacob Werner, a Blackstone real estate managing director, said the firm is “bullish” on Chicago, with companies expanding and moving to the city, with demand for first-class office space.

“We see great potential in further improving both the building’s retail operations and the tourist experience for one of the most popular destinations for visitors to Chicago,” Werner said.

KGAL last month said that, along with UBS, it had jointly sold an office building in Chicago’s central business district at 30% above market value.

LaSalle Investment Management last year invested in its home city, buying an office property for Germany’s largest pension fund group BVK.

The investment manager bought 101 North Wacker Drive from Hines on behalf of BVK’s Bayerische Ärzteversorgung (BÄV) umbrella fund for doctors, lawyers and architects.