Although Wellmark Blue Cross and Blue Shield has not announced the location of its new headquarters in Central Iowa, a principal at RDG Planning & Design said his company is designing a building for a location in downtown Des Moines.

Al Oberlander told the Business Record that RDG is working on plans for a building north of the Gateway West area that would enclose 500,000 square feet. He later retracted that statement, reporting that RDG principal Davis Sanders said no location has been selected.

Norm Bower, a publicist for KJWW Engineering Consultants in Rock Island, Ill., said his company also is working on plans for a $100 million project to consolidate Wellmark’s downtown offices. He said various locations are being considered.

Wellmark spokeswoman Angela Feig acknowledged that work on “very preliminary plans” could be under way, but a decision about whether to build downtown or in West Des Moines won’t be made until August.