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. With our planned disposition program complete, today over half our portfolio revenues are derived from gateway markets, including New York, San Francisco, Washington D.C., and Boston, 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-adding capital improvements, which results in strong rental rates and maintains 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 76% of our buildings ENERGY STAR®-certified and nine 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.