Creative Planning Inc., a registered investment advisor headquartered in Overland Park, Kan., has acquired the retirement division of Northbrook, Ill.-based IRON Financial, the companies announced.

IRON's retirement division brings $6 billion in AUM to Creative Planning, which now manages over $69 billion in total assets nationwide. Financial details of the transaction were not disclosed.

"We are excited to bring the IRON Financial retirement division into our fold," Peter Mallouk, CEO of Creative Planning, said in a news release. "IRON Financial is a well-established firm with an innovative approach that aligns perfectly with our values and vision."

IRON Financial was founded in 1994 by Aaron Izenstark and Howard Nixon, two former bond traders.

Richard Friedman, head of corporate retirement services at IRON Financial, indicated in the news release that Creative Planning was the right partner at the right time.

"We have built one of the premier fiduciary services in the country and knew it was time to expand our scale and offering," he said in the news release. "When it comes to a best-in-class, industry-leading fiduciary offering, Creative Planning stood as the clear choice for us. This helps us serve our clients and team better by providing a broader investment policy and research team, expanded technology, greater scale and more services."

Founded in 1983, Mallouk acquired Creative Planning in 2004 after working five years with the firm as an estate planner.