CoreSite Issues 2018 Corporate Sustainability Report 

CoreSite Realty Corporation (NYSE:COR), (the "Company") a premier provider of secure, reliable, high-performance data center and interconnection solutions in major U.S. metropolitan areas, today announced it has issued its "2018 Corporate Sustainability Report ? Another year into our journey," which is posted on the Company's website.

"Customers, Colleagues, and Communities are three words to describe how our business strategy intertwines with our sustainability practices," said Paul Szurek, CoreSite's President and Chief Executive Officer. "Since 2001, CoreSite has been committed to best-in-class customer experience and value, an engaging, attractive and diverse employment environment, and practices that help our customer communities thrive sustainably, In our second Corporate Sustainability Report, we summarize our ongoing journey of being a responsible steward of our business for all our stakeholders."

Below are a few 2018 highlights from the 2018 Corporate Sustainability Report.

Customers ? CoreSite's energy efficient data centers

CoreSite seeks the least carbon-intensive generation sources consistent with its customers' economic goals and options permitted in its markets. As part of that objective, CoreSite's 2018 accomplishments included -

• completing a chiller project for more than 9,800 MW of energy savings achieved in 2018 at its LA2 data center and being awarded nearly $3 million by the Los Angeles Department of Water and Power for this project and its savings
• achieving "Seven 9s" of reliability across its platform of data center facilities, resulting in high customer satisfaction, and
• improving its 2018 Power Utilization Effectiveness by about 7% on a same-store basis compared to 2017.

Colleagues ? A culture of responsibility, transparency, innovation and operational excellence

CoreSite continues to shape its culture by empowering its employees and valuing their diversity and leadership, which ultimately drives the Company's success and that of our stakeholders. Key metrics for 2018 included -

• women represented 41% of CoreSite's headquarters workforce and 20% of its Board of Directors
• minorities and veterans represented 42.3% and 14.5%, respectively, of its total workforce, and
• an average workforce tenure of 4.1 years.

Communities ? Rich ecosystem of customers that work seamlessly together

CoreSite enables customers to interoperate securely and reliably, promoting their use of shared infrastructure, which reduces their collective data center footprint. With CoreSite's valuable eco-system, customers can -

• access 75% of U.S. business within 5 milliseconds,
• connect to over 775 network, Internet, cloud and IT service providers, as well as connect to over 525 enterprises and digital content providers, and
• access Cloud direct connections in all eight of CoreSite's markets.

"A formal Corporate Sustainability program is a continuous quest, and I look forward to the road ahead, as we persist in focusing holistically on a broad range of success measures that take into account all of our stakeholders," said Szurek.

About CoreSite

CoreSite Realty Corporation (NYSE:COR) delivers secure, reliable, high-performance data center and interconnection solutions to a growing customer ecosystem across eight key North American markets. More than 1,350 of the world's leading enterprises, network operators, cloud providers, and supporting service providers choose CoreSite to connect, protect and optimize their performance-sensitive data, applications and computing workloads. Our scalable, flexible solutions and 450+ dedicated employees consistently deliver unmatched data center options ? all of which leads to a best-in-class customer experience and lasting relationships. For more information, visit www.CoreSite.com.

Forward Looking Statements

This press release may contain forward-looking statements within the meaning of the federal securities laws. Forward-looking statements relate to expectations, beliefs, projections, future plans and strategies, anticipated events or trends and similar expressions concerning matters that are not historical facts. In some cases, you can identify forward-looking statements by the use of forward-looking terminology such as "believes," "expects," "may," "will," "should," "seeks," "approximately," "intends," "plans," "pro forma," "estimates" or "anticipates" or the negative of these words and phrases or similar words or phrases that are predictions of or indicate future events or trends and that do not relate solely to historical matters. Forward-looking statements involve known and unknown risks, uncertainties, assumptions and contingencies, many of which are beyond CoreSite's control that may cause actual results to differ significantly from those expressed in any forward-looking statement. These risks include, without limitation: the geographic concentration of the Company's data centers in certain markets and any adverse developments in local economic conditions or the amount of supply of or demand for data center space in these markets; fluctuations in interest rates and increased operating costs; difficulties in identifying properties to acquire and completing acquisitions; significant industry competition, including indirect competition from cloud service providers; failure to obtain necessary outside financing; the ability to service existing debt; the failure to qualify or maintain its status as a REIT; financial market fluctuations; changes in real estate and zoning laws and increases in real property tax rates; and other factors affecting the real estate industry generally. All forward-looking statements reflect the Company's good faith beliefs, assumptions and expectations, but they are not guarantees of future performance. Furthermore, the Company disclaims any obligation to publicly update or revise any forward-looking statement to reflect changes in underlying assumptions or factors, of new information, data or methods, future events or other changes. For a further discussion of these and other factors that could cause the Company's future results to differ materially from any forward-looking statements, see the section entitled "Risk Factors" in its most recent annual report on Form 10-K, and other risks described in documents subsequently filed by the Company from time to time with the Securities and Exchange Commission.