It is time to pay attention to the office buildings on Michigan Avenue as they are getting interest from investors. Last week, CIM Group put the office portion of 625 North Michigan on the market. Now comes news that a marquee building two blocks south is changing hands. Walton Street Capital has agreed to buy 401 North Michigan from Zeller Realty, Crain's Chicago Business reports.

Walton Street is paying $370M for the 35-story building. Zeller bought the building from Equitable Life Insurance for $120M in 2001 and has repositioned the property with capital improvements. Apple is paying $27M to build an Apple Store that will include improvements to the riverwalk next to the building. Zeller is believed to be retaining a small ownership stake in the building and will remain on board as property manager.

The $370M price tag would make 181 West Madison the top downtown office sale of 2017, knocking down a $360M sale in February. And 401 North Michigan may not hold on to that distinction for long. CBRE Global Investors is seeking $400M bids for 161 North Clark, which it put up for sale a couple of weeks ago.