Hubbell Realty Co. will place the Kaleidoscope at the Hub on the market today with an asking price of $2,515,000.

The downtown mall at 555 Walnut St., which Hubbell developed in 1985, includes two buildings linked by a skywalk bridge over Sixth Avenue.

Colleen Johnson, a broker and vice president with CB Richard Ellis/Hubbell Commercial who specializes in retail properties, said the changing landscape of the central business district is driving Hubbell's decision to list the property.

"There may be other developers that may specialize in exploring opportunities," for the 159,707-square-foot property, she said, which includes about 98,000 square feet of leasable space.

As the downtown office market prepares to absorb an estimated 750,000 to 1 million square foot of competitive office space, with Wellmark Blue Cross and Blue Shield of Iowa's and Aviva USA's moves to owner-occupied campuses, Hubbell sees big opportunities for the area to evolve.

As the planned relocation of Des Moines Area Regional Transit Authority's transit mall from Walnut Street moves ahead, Hubbell is homing in on its vision to turn the Kaleidoscope into a full-blown retail outlet, which has been a goal of the West Des Moines-based developer since early 2009, when CitiMortgage and Principal Financial Group Inc. vacated approximately 36,000 square feet of office space on the ground level.

"I think that brings in some really exciting concepts, to strengthen downtown," Johnson said, noting that Hubbell will continue to explore the option of recdeveloping the property as it seeks a buyer. "We can bring in new retail concepts," she said, adding that Hubbell has studied emerging retail districts in Omaha, Kansas City and Louisville, Ky.

Johnson said the Kaleidoscope's vacancy rate stands at 54 percent, which includes six vacant bays on its skywalk level. According to the Polk County assessor's website, 555 Walnut St. has an assessed value of $2,000,000.