Thomas Properties Group announced a second-quarter net loss and said that it had exercised an option to buy out a long-time joint venture that owns downtown’s City National Plaza and some out-of-state properties.

After the markets closed on Thursday, the Los Angeles real estate company reported a loss of $5.6 million (-12 cents a share) compared with a loss of $4.8 million (-12 cents) in the same period a year earlier. Revenue rose 3 percent to $7.9 million.

Thomas Properties also said that it exercised its option buy out part of an investment partnership with the California State Teachers’ Retirement System that had been in place since 2003. The partnership owned City National Plaza and properties in Virginia and Houston. Thomas is maintaining its Austin, Texas joint venture with CalSTRS, but its percentage of ownership has increased from 6.25 percent to an effective interest of 33.3 percent.

“We are pleased with our continued progress toward achievement of our strategic plan,” Chief Executive Jim Thomas said in a statement.

Several items weighed on the Thomas Properties’ bottom line during the quarter, including the company taking more ownership of the Austin properties and hence a larger potential liability for any losses. There also were $3.4 million in expenses related to settlement of a lawsuit.

Shares on Friday closed up 6 cents, or 1 percent, to $5.73 on the New York Stock Exchange.