Baltimore County (Md.) Employees Retirement System committed $10 million to HarbourVest Partners Fund VI, said Robert Burros, investment administrator. The $1.8 billion system previously committed $30 million to HarbourVest Partners Fund V. The system has a private equity allocation of up to 3%. So far, it has committed 1.8%, and 0.7% has been invested, Mr. Burros said. Funding is from maturing real estate investments.