The conservative nature of the Des Moines marketplace has been tested in the past 24 months yet cautious optimism prevails. Historically the high concentration of financial service and insurance companies translated into quick absorption of large blocks of space. However, the downturn in the economy and the move of companies such as Allied-Nationwide, Wellmark Blue Cross/Blue Shield and Aviva to new, owner-occupied buildings left behind significant blocks of space that have increased the office vacancy rate to almost 19 percent and will send it even higher. New construction and development has been divided between the central business district (CBD) and the west suburban markets. The 152,000-square-foot Davis-Brown Tower and the Wellmark’s 550,000-square-foot headquarters are significant additions to the CBD Gateway West corridor, while Aviva’s 360,000-square-foot, United States headquarters is situated in the ever-emerging Jordan Creek corridor. Although development of smaller office buildings has been slowed, there are some signs of positive growth. Delta Dental Iowa is nearing completion of its new 25,000-square-foot headquarters at Northpark Office Park in Urbandale. In addition, two significant lease transactions were signed in the west suburban market, including 25,000 square feet for Strategic America at 6600 Westown Parkway and 93,000 square feet for Sammons Financial …