Los Angeles-based property manager and developer Arden Realty Inc. has agreed to purchase a portfolio of 106 West Coast office buildings from CarrAmerica Realty Corp., the Business Journal has learned.

The 5.9 million-square-foot portfolio includes properties in Orange and San Diego counties, as well as Northern California, Portland and Seattle. Financial terms were not immediately available.

“This acquisition accelerates our growth objectives for this year,” stated Arden Chief Exeuctive Joaquin de Monet, in a prepared statement. “It also reflects two important components of our strategy: our strong commitment to our core markets and the blueprint for our new target markets throughout the West Coast.”

Developer and property manager CarrAmerica is a subsidiary of private equity firm Blackstone Group LP, which purchased the Washington D.C.-based company for $5.6 billion last year. CarrAmerica will retain nearly 20 million square feet of property once the deal closes in August.

The deal comes amidst a busy cycle for Arden, which was acquired last year by GE Real Estate, a division of General Electric Co.. Since then, Arden has been steadily selling off pieces of its portfolio and will have purchased about $850 million of new properties by the end of the second quarter.

In May, the Business Journal reported that Arden agreed to sell a 33-property portfolio to Cabi West Coast Acquisitions LLC for just under $1.5 billion. Cabi West is the local subsidiary of GISCA, one of Mexico’s largest real estate developers.

That 4.6 million-square-foot portfolio includes properties in Los Angeles, San Diego, Orange and Ventura counties. The deal closes July 10. Arden owns about 10 million square feet of Southern California office space.