Cornerstone Properties Divests Denver Property.

NEW YORK--(BUSINESS WIRE)--Dec. 13, 1999--

Cornerstone Properties Inc. (NYSE:CPP) announced today that it has sold One Norwest Center to Commonwealth Partners, in joint venture with California Public Employees Retirement System, for $208.5 million. The 50-story, 1.2 million square foot Class A office tower, which was completed in 1983, is located in the heart of Denver's Central Business District. Designed by Philip Johnson and John Burgee, One Norwest Center is a signature building on the downtown Denver skyline.

One Norwest Center was Cornerstone's first asset, built as a joint-venture between the Company and Gerald D. Hines Interests. The property was owned in partnership by both companies until 1995, when Cornerstone purchased Hines' partnership interest. The tower has been managed by Hines and anchored by The Norwest Corporation from 1983 to the present and has maintained an average occupancy rate of approximately 97% over that period.

John S. Moody, President and Chief Executive Officer of Cornerstone Properties, commented, "One Norwest Center is a high-quality, distinctive property that we've been proud to have in our portfolio. As our first asset, One Norwest provided the foundation upon which our high-quality portfolio has been built. While One Norwest fits our investment criteria relative to size, quality and tenant base, Denver is not one of the metropolitan areas where we want to build our presence going forward. Including this transaction, we have disposed of over $450 million worth of non-core assets year-to-date, and will recycle that capital to those markets where we can better leverage our property management, leasing and development capabilities."

Brett Munger, CommonWealth Partners Chief Investment Officer, commented, "We are very excited to have One Norwest Center as our first acquisition in the Denver area. This is an exceptional property of the highest quality with a terrific tenant roster. The city and local business community have done an outstanding job of creating a dynamic business environment in Denver. We are proud to establish a presence here and look forward to future investment opportunities in the area."

Lazard Freres acted as advisor to Cornerstone Properties in the transaction.

Cornerstone Properties is a fully-integrated real estate investment trust (REIT) with a full range of development, acquisition, management and leasing capabilities. The company currently owns 86 Class A office properties throughout the U.S. totaling over 17 million square feet and has an additional $752 million of projects under development. The properties are located in the major suburban markets and central business districts of Seattle, Northern and Southern California, Minneapolis, Chicago, Boston, New York, Washington, D.C. and Atlanta. For more information visit the Cornerstone Properties website at www.cstoneprop.com. To sign up for our press release e-mail list, go to www.cstoneprop.com/e-mail.

CommonWealth Partners, a fully integrated real estate development and investment company, formed a joint venture with CalPERS and is the exclusive investment partner for CalPERS' Southwestern Region Office Portfolio of approximately $1 billion. Together, CWP and CalPERS created an independent, privately funded operating company with the discretion, capital and resources to acquire, development manage, and lease office and mixed use investments throughout the southwestern United States.

This press release contains forward-looking statements within the meaning of the Federal securities laws. Forward-looking statements are inherently subject to risks and uncertainties, many of which cannot be predicted with accuracy, that could cause the actual results, performance or achievements of Cornerstone to differ materially from those reflected in such forward-looking statements. Information contained in this press release regarding current and future market conditions is based on Cornerstone 's assessment of real estate markets as of this date and is subject to the uncertainties inherent in such an assessment. In particular, but not exclusively, national and regional economic conditions, the rate of new construction, and demand and supply in a given market will affect leasing activity, projected rents and the cost of lease renewals. Please see our SEC 10-Q and 10-K filings for updates to this list of risks and uncertainties.