[pullmanman]

Crain's Chicago Business Danny Ecker

Serving small businesses is quickly turning ActiveCampaign into a big one, and it's adding a chunk of new office space to accommodate its growth.

After doubling its total workforce since early last year to around 500 employees, the 16-year-old marketing software company is nearly doubling the size of its office at 1 N. Dearborn St. to about 115,000 square feet, CEO Jason VandeBoom said.

Ramping up its team with about 180 new hires last year, ActiveCampaign subleased about 15,000 square feet on the building's eighth floor from logistics software company FourKites to give its employees a little more room to work with. Now it is hoping another floor will help its capacity issue, though VandeBoom said it will be hard to keep pace with the company's growth.

"We are a quiet company that is scaling up under the radar in Chicago," he said. "We're an example of having hyper growth, but sustaining it from a customer base that's demanding it."

If smaller companies like this keep expanding in the Loop that should help make up for the slowly contracting amount of space leased by law firms, and the big additions of the Post Office and various other new builds.