Private equity investment firm Odyssey Investment Partners LLC made an investment in Chicago-based professional staffing firm Addison Group and is now the majority owner.

The transaction is expected to close prior to the end of the year, at which time Trilantic Capital Partners will exit the investment it made in Addison in 2013. Financial terms were not disclosed and no management changes are planned.

The investment will support Addison Group’s organic and acquisition growth strategy, according to the company.

“After several years of sustained growth, Addison Group’s partnership with Odyssey arms us with significant capital to propel our growth strategy to the next level, said Addison Group CEO Thomas Moran. “We will remain highly focused on expanding nationally through organic opportunities, while also continuing to add tuck-in acquisitions that complement our business model and culture.”

Addison Group has 18 offices nationwide and more than 650 employees. Targeted sectors include IT, finance and accounting, healthcare, executive search, HR and administrative, and engineering. The company’s acquisition interests include companies with similar lines of business and workplace culture that will expand Addison Group’s geographic footprint.

Odyssey Investment Partners makes majority controlled investments and targets middle-market companies. It has offices in New York and Los Angeles, and has raised more than $5.0 billion of private equity capital since inception, investing in more than 40 platform companies and more than 125 add-on acquisitions. Odyssey is currently investing out of its fifth fund, a $2.0 billion vehicle raised in 2014.