PHOENIX—There's no space like trophy space. The premiere office towers that make up Phoenix's skyline boast—by far—the most expensive office space to rent, garnering asking rents that are 33.5% higher than non-trophy space, according to JLL's 2015 Digital Skyline. Average Phoenix trophy rates in the first quarter of 2015 were $26.53 per square foot, compared to $19.87 per square foot in non-trophy buildings. This gap between local trophy and non-trophy space is approaching peak historical spreads: 10 years ago, the difference was 37.6%.

“Owners of the Valley's trophy buildings recognize the leasing power of top-end amenities,” says JLL managing director John Bonnell. “As Phoenix's economy improves, owners from The Esplanade to CityScape are taking the initiative to make sure those flight-to-quality amenities are in place, and that trophy properties earn their position in the marketplace.”

According to JLL, the flight to quality in earlier recovery years coupled with an improving economy today have led to significant supply constraints in the country's highest-quality office buildings. But while fundamentals are expected to tighten in many U.S. cities, drawing attention to other asset classes, the same may not be true for Phoenix. In contrast, the JLL report ranks Phoenix trophy space as “neutral” for landlord versus tenant leverage through 2017.