This is a report on why commercial office buildings aren’t more energy efficient. Several decades of energy efficiency programs have resulted in some gains, but overall increases in the energy efficiency of buildings have fallen far short of the 30 to 50 percent improvement that many efficiency advocates believe is possible. The purpose of this study is to consider the “why” question by empirically examining the dynamics of new commercial building markets. To do so, the authors used multiple research techniques, including qualitative field observation and interview methods that allow for a more in-depth understanding of complicated market processes. Their research focused primarily on new office buildings and centered in four regional markets: Sacramento, San Francisco, Seattle, and Portland. The authors identify key dynamics of commercial office building markets, describe how change and innovation occurs in commercial development, discuss the implications for energy efficiency, and suggest next steps.