Shares in Philippine food and beverage giant San Miguel Corp soared on Thursday after it announced plans to buy into one of its stakeholders in a defensive move by management to maintain control of the firm.

San Miguel announced Wednesday it would acquire 49 percent of Top Frontier Holdings Inc., a company that owns about 26 percent of San Miguel's outstanding stock.

Top Frontier, which is owned by San Miguel directors Roberto Ongpin and Inigo Zobel, is set to become San Miguel's biggest shareholder after it recently announced plans to acquire another 20 percent from Q-Tech Alliance.

San Miguel shares climbed 7.46 percent to close at 72 pesos (1.57 dollars) on Thursday in the first market reaction to the announcement.

While Ongpin is seen as an ally of San Miguel president Ramon Ang, San Miguel's acquisition of Top Frontier ensures that San Miguel's current management cannot be easily changed.

"It's a strategy for them to have greater management stability," Patrick Elia, an economist with Security Bank, told AFP.

"The most important thing there is that the same people who managed SMC in the past will most likely be managing it after this takeover (of Top Frontier)."

Elia said that Top Frontier is poised to become the single biggest owner of San Miguel once it acquires the San Miguel shares of Q-Tech Alliance.

Additionally, once the acquisition of the Q-Tech shares is completed, Top Frontier will be required by law to make a tender offer for the remaining shares of San Miguel, which could boost its ownership of the company further.

Sources within San Miguel told AFP the 120-year-old company had been aware that Top Frontier was bent on acquiring more of its shares and that its financial and legal advisers warned Ang's team to buy into Top Frontier.

Ang has been leading San Miguel's thrust away from its core businesses of beer, beverages, food and packaging and into such areas as utilities, infrastructure and mining.