Glendale health management company Apollo Medical Holdings Inc. has signed a definitive agreement to merge with Network Medical Management Inc. of Alhambra, the companies announced Thursday. Combining in a stock-for-stock transaction, the new entity will retain the name Apollo Medical Holdings. However, health care management services organization Network Medical stockholders will own 82 percent of the new company, while ApolloMed investors will own the remaining 18 percent. Dr. Warren Hosseinion, current chief executive of ApolloMed, and Dr. Thomas Lam, current chief executive of Network Medical, will lead the company together as co-chief executives. “We are excited to announce this strategic transaction with Network Medical Management to create one of the leading population health management companies in the nation,” Hosseinion said in a statement. “The merger will create a platform with a comprehensive suite of solutions for physicians, hospitals, health plans and accountable care organizations.” The transaction is expected to close in the first half of 2017 subject to regulatory clearance, closing conditions and shareholder approval. The boards of both companies have approved the merger. ApolloMed (AMEH) shares closed up 96 cents, or 24 percent, to $4.95 on the over-the-counter market.