Financial terms of the deal were not disclosed.
Arizona-headquartered WealthPlan Advisors provides retirement plans and investment consulting to its nearly 600 clients with assets of more than $2.3bn.
The acquisition is expected to help Hub augment its suite of retirement and wealth advisory services.
Hub Southwest president Randy Perkins said: “Expanding our retirement and wealth advisory services in our region is of critical importance as we continue to add value for our clients and as their needs continue to grow.”
Following the transaction, WealthPlan Advisors team will join the Hub Southwest region.
Hub Retirement and Wealth Management president Joe DeNoyior commented: “We are excited to welcome the whole WealthPlan Advisors team and clients to Hub.
“WealthPlan Advisors will be a tremendous asset to our clients and will allow us to continue expanding our retirement and wealth planning services in the Southwest and across the US.”
WealthPlan Advisors president Scott Schlappi said: “Joining Hub is an exciting new chapter for our firm.
“Hub continues to grow in the retirement and wealth planning space, and the amount of talent, resources and tools they have is a win for us and will greatly benefit our clients.”
Chicago-headquartered Hub has been accelerating its organic growth and M&A strategy to expand its geographical footprint and industry presence. The firm has also been growing its presence in the wealth and retirement segment in recent years.
In June, Hub acquired the assets of Pennsylvania-based independent financial services firm Heritage Wealth Management.