Tycoon Henry Sy Sr. is finalizing a deal to acquire a majority stake in the privately held Ortigas property group in a transaction worth around $1 billion, seen as a potential “game-changing” move that will expand the SM group’s landbank in the metropolis and give it control of the 16-hectare Greenhills shopping complex.

Inquirer sources confirmed that the SM group was close to a deal to buy into the Ortigases’ property holding unit OCLP Holdings after a crucial bloc, which included British banking giant HSBC and some family members, consented to the deal.

The sources said that HSBC, the single biggest stockholder of OCLP with a stake of 34 percent in the property unit, has already signed some documents approving the sale. On the other hand, there was likewise a critical mass of Ortigas family members who had agreed to the transaction, aiming to unlock more values from their vast landholding.

The target was to finalize all documentation by March, at the latest, one source said.

Shares of Sy-affiliated companies, particularly SM Investments Corp. and SM Prime Holdings, outperformed Wednesday due to the excitement on this prospective transaction with the Ortigas group.

SM Prime surged 4.7 percent to P15.60 a share while SMIC was up 2.4 percent to P692 each.

Jose Mari Lacson, head of research at local stockbrokerage Campos Lanuza & Co., said this was a potential “game-changer” move that could propel the SM group’s SM Land or SM Development Corp. to the size of Ayala Land Inc.

“It allows them to secure a large landbank in a major central business district. Ayala can now pick on somebody its own size,” Lacson said.

The Ortigas group has a vast urban landbank spanning Mandaluyong, San Juan and Quezon City, the crown jewel of which is Greenhills shopping center.

It is not yet known which SM unit or units will take part in the transaction but SM Prime is seen benefiting significantly given the Greenhills landbank.

“Only SMIC can muster that money without straining its balance sheet too much,” Lacson said. He added that the group could also choose to use SM Land but this unit would have to raise cash, although a share-swap was also seen as a possibility.

Just last week, SM Investments raised $250 million from the sale of five-year bonds convertible into equity.

Both the SM and Ortigas groups declined to comment on the prospective transaction Wednesday.

The Inquirer reported last December that the Ortigases have restructured their core unit into a new corporate entity to prepare for either the entry of a new strategic investor or a stock market debut.

Industry sources said HSBC had initiated the move to transform the closely held limited partnership Ortigas & Co. into a corporation. Under a limited partnership, general partners team up with one or more limited partners who, in turn, enjoy limited liability as long they do not participate in the control of the business. The general partners under this structure are the ones who carry more liability.