Columbia Property Trust is focused on creating value in high-barrier U.S. office markets, while maintaining a strong balance sheet. Since 2011, we have undergone a significant transformation through opportunistic acquisitions and dispositions, shifting our focus from suburban and mostly single-tenant properties to predominantly CBD and multi-tenant properties. Today our portfolio value is concentrated in select gateway markets, primarily New York, San Francisco, and Washington D.C., where our operations are led by strong local teams.
As an owner/operator, we strive to maximize returns through proactive management, creative leasing and value-enhancing capital improvements, which together drive strong rental rates and high occupancy in our portfolio. We also seek to operate efficiently, responsibly and always in the best interest of our stakeholders. We are proud to have 80% of our buildings ENERGY STAR®-certified and seven of our buildings LEED®-certified, and we are pursuing certification for additional properties.
To learn more about our strategy please review our latest Investor Presentation.