see - sc.judiciary.gov.ph/jurisprudence/2013/july2013/174912.pdf
"x x x.
In one case, the Court held that it is management prerogative to farm out any of its activities, regardless of whether such activity is peripheral or
core in nature.44 What is of primordial importance is that the service
agreement does not violate the employee's right to security of tenure and
payment of benefits to which he is entitled under the law. Furthermore, the outsourcing must not squarely fall under labor-only contracting where the contractor or sub-contractor merely recruits, supplies or places workers to perform a job, work or service for a principal or if any of the following
elements are present:
i) The contractor or subcontractor does not have substantial capital or investment which relates to the job, work or service to be performed and the employees recruited, supplied or placed by such contractor or subcontractor are performing activities which are directly related to the main business of the principal; or
ii) The contractor does not exercise the right to control over the performance of the work of the contractual employee.45 ."