G.R. No. 190187 - Philippine Geothermal, Inc. Employees Union vs. Unocal Philippines, Inc.

Petitioner Philippine Geothermal, Inc. Employees Union is the certified bargaining agent of the rank-and-file employees of Unocal Philippines, Inc.
Respondent Unocal Philippines, Inc. (formerly Philippine Geothermal, Inc.) is a wholly-owned Philippine subsidiary of Union Oil Company of California, which in turn is a subsidiary of Union Oil Corporation; it operates geothermal steam fields in Tiwi, Albay and Makiling-Banahaw, Laguna under lease from the National Power Corporation.

On April 4, 2005, Unocal Corporation executed a Merger Agreement with Chevron Texaco Corporation and its subsidiary Blue Merger Sub, Inc.; Blue Merger survived and was renamed Unocal Corporation, making Chevron the ultimate parent.
On January 31, 2006, Unocal Philippines and the Union executed a Collective Bargaining Agreement (CBA). On October 20, 2006, the Union demanded separation benefits under the CBA, claiming that the parent-company merger impliedly terminated its members’ employment; Unocal Philippines refused.

The parties submitted to DOLE voluntary arbitration. On January 15, 2008, the Secretary of Labor ruled that the merger impliedly terminated the employees and awarded separation pay under the CBA.
Unocal Philippines appealed to the Court of Appeals. On July 23, 2009, the CA reversed the Secretary of Labor’s decision, holding that Unocal Philippines was not dissolved and its employees were unaffected. The CA denied the Union’s motion for reconsideration on November 9, 2009. The Union then filed the present Petition for Review on Certiorari before the Supreme Court.

Whether respondent changed the theory of its case on appeal by first claiming it was not a party to the Merger Agreement.
Whether the Merger Agreement of Unocal Corporation, Blue Merger, and Chevron impliedly terminated the employment of the Union’s members.
Whether the Union’s members are entitled to separation benefits under the CBA as a result of the merger.