Goldman Sachs Group Inc. Is moving to obtain 100% ownership of its securities joint venture in China, deepening its investment in the world’s second-biggest economy after joining with a domestic brokerage for 17 years.The New York-based bank is applying with Chinese regulators to take complete control of Goldman Sachs Gao Hua Securities Co. and has signed an agreement to obtain the 49% share of the venture it does not own, according to the internal memo seen by the Wall Street Journal.Goldman is the first worldwide bank to seek full ownership of its securities business in China and plans to rename it Goldman Sachs (China) Securities Co. In March, the country’s securities regulator approved the firm’s bid to take full control of the Beijing-based unit.