The CB Richard Ellis investment team of Mary Sullivan, Ron Urgitus and Tim Swan sold the building. Sullivan says that most of the 34 bidders came very close in their offers. "It was one of those deals where you hated to call up the people to tell them they lost," Sullivan tells GlobeSt.com. "A lot of qualified buyers really wanted this building for their portfolios."

PGI, which owns several other Downtown and suburban Denver buildings, was drawn to the quality of the building. It was built in the mid-1980s in a joint venture between its anchor tenant, Security Life, and Central Development, which included George Beardsley and Al Cohen, who also were founders of the Inverness Business Park south of the Denver Tech Center. At one time, Cohen, who owned a construction company, tried to convince the city to build a new convention center in the nearby Golden Triangle neighborhood.

Part of the appeal of the location is that across the street the Museum Residences are being built, Sullivan tells GlobeSt.com. Those condos are being designed by famed New York architect Daniel Libeskind, who created the master plan for the World Trade Center replacement in New York. These are his first US condos.

"Those units are selling for $500 per sf," Sullivan tells GlobeSt.com. "If not the most expensive condos in Denver, they're certainly up there. It's a real testament to the neighborhood."

Indeed, the purchase includes an adjacent half block, where it's likely another high-rise, luxury residential tower will be developed. Sullivan says the building, which was designed by Michael Barber, has a timeless quality, with its glass, granite and high-end features. Security Life's office was designed by locally based RNL. Sullivan says the replacement cost is at least $200 per sf, about $60 more per sf than what the buyer paid.

Some developers, however, think it has an odd location, as it is not in the Central Business District. Others note that the building was designed with large floorplates best suited for single tenants, rather than multi-tenant buildings that are easier to lease.