Gilbert’s Rock Ventures, the umbrella entity overseeing his portfolio of companies and investments, announced today it has purchased the historic One Woodward office tower at Woodward and Jefferson Avenue.

The 333,000-square-foot, 26-story building is about 60% occupied. Major tenants include the Detroit Regional Chamber and the law firms Fraser Trebilcock Davis & Dunlap, and Kitch Drutchas Wagner Valitutti & Sherbrook.

As with Gilbert’s other downtown buildings, Rock Ventures plans to renovate the building to accommodate what Gilbert envisions as the city’s emerging roster of technology employers.

Built in 1962, One Woodward was designed by famed architect Minoru Yamasaki and was originally built for the Michigan Consolidated Gas Co., now part of DTE Energy. The design is often called an early predecessor of the Yamasaki design for New York’s World Trade Center.

“We continue to bet big on Detroit, and this purchase reinforces our commitment to the exciting entrepreneurial action on Woodward Avenue,” Gilbert said in a statement.

“The One Woodward building is located in the heart of Detroit’s technology core, and provides us more space to further accommodate our growing family of companies and the increasing number of businesses that want to leverage the opportunities made in Detroit,” Gilbert said.

The building occupancy rate will top 90% next month when Quicken Loans and its affiliates lease a total of eight floors in the building.

The purchase of One Woodward building was co-brokered by Friedman Integrated Real Estate Solutions and Bedrock Real Estate Services LLC, Rock Ventures’ full-service real estate firm and developer for the project. Bedrock will also be responsible for overseeing the renovations, managing the property and leasing the space.

 Since January 2011, Rock Ventures has purchased 10 buildings totaling nearly 2.5 million square feet of office space, plus two parking garages with 3,500 parking spaces.  Last month, the company broke ground on a 33,000-square-foot specialty 10-story parking garage in with ground floor retail in downtown Detroit.

Contact John Gallagher: 313-222-5173 or gallagher99@freepress.com

Gilbert’s other real estate holdings

In addition to the One Woodward tower, here are Dan Gilbert’s other real estate holdings in downtown Detroit:

1. The M@dison, 1555 Broadway St., 50,000 square feet

2. Chase Tower, 611 Woodward Ave., 505,000 square feet

3. First National Building, 660 Woodward Ave., 800,000 square feet

4. Chrysler House (the former Dime Building), 719 Griswold St, 320,000 square feet

5. Historic Federal Reserve Building, 160 W. Fort St., 176,000 square feet

6. Wright-Kay Building, 1500 Woodward Ave., 24,000 square feet

7. Lane Bryant Building, 1520 Woodward Ave., 43,702 square feet

8. Arts League of Michigan Building, 1528 Woodward Ave., 45,146 square feet

9. 1550 Woodward, 4,052 square feet

10. Two Detroit Center Parking Garage, 160 E Congress St., 1,107 parking spaces

11. Financial District Garage, 730 Shelby St., 934 parking spaces

12. Z-Lot Development (to be completed December 2013), Corner of Broadway & East Grand River, 33,000 square feet retail; 1,300 parking spaces