Aecom Technology Corp. on Wednesday said that it completed most of a $324 million acquisition of project management firm Davis Langdon as the Los Angeles consultant continues to diversify its business.

Davis Langdon, which is based in London and has operations in Australia, New Zealand, Europe, the Middle East and the United States, has 2,800 employees that serve government and private-sector clients. The acquisition of Davis Langdon’s South Africa operations is expected to be completed by the end of October.

Aecom, which provides professional technical and management support services, has announced nearly $1 billion in acquisitions so far this year. The company in August agreed to buy McNeil Technologies Inc. in Springfield, Va., for about $355 million. In July, it acquired New York City’s Tishman Construction Corp. for $245 million in cash and stock, and bought a Madrid professional technical services firm called Inocsa in May for an undisclosed amount.

The company said the acquisitions are expected to add approximately $1.7 billion in annual gross revenue.

Shares were down 10 cents, or less than a percent, to $24.27 in midday trading on the New York Stock Exchange.