Conversation so far:
What background can you give me on the Merchandise Mart?
The Merchandise Mart (or the Merch Mart, or the Mart) is a commercial building located in downtown Chicago, Illinois.
What other businesses participate in the Merchandise Mart?
It has become home to several other enterprises, including the Shops at the Mart, the Chicago campus of the Illinois Institute of Art,  and Motorola Mobility.
How big is the Merchandise Mart building space?
When it was opened in 1930, it was the largest building in the world, with 4,000,000 square feet (372,000 m2) of floor space.
What are the financial stats for the Merchandise Mart?

Question: How is commerce involved with the Mart?
Self-contained rewrite: How is commerce involved with the Merchandise Mart?