Researchers say sale prices spiked to $200 per sf, a $67 increase from last year. For three consecutive quarters, office sale prices increased about 20% due to stronger market fundamentals, says Scott Price, national director of research for Delta Associates. "Increasing sales prices are a phenomenon across the country, but Phoenix is slightly higher than other markets," he says.

Top of the market deals to date include Los Angeles-based Maguire Properties Inc.'s sale of One Renaissance Square for $118 million or $244 per sf to the Pauls Corp. of Denver. Also selling in the first six months were Camelback Esplanade I and II, which garnered $311 per sf or $162 million from Metropolitan Life Insurance Co.

Price tells GlobeSt.com that total returns on Valley office properties are rising due to rent hikes and overall price increases. He says cap rates for institutional-quality assets are in the mid-7% range. He predicts cap rates will rise moderately over the next two years.