In the case of Northern Superior Supply Co., the Ontario Labour Relations Board held that only the payroll of an employer’s operation in Ontario is relevant to s. 64(1)(b) [of the ESA]. The Board held that Ontario has legislative authority with respect to businesses operating in Ontario and has no authority to legislate concerning payrolls in other provinces.
 The Board relied on the decision of the Divisional Court in Tullett and Tokyo Forex (Canada) Ltd. v. Singer in which the court held that an employee of a Canadian subsidiary of a U.S. company who had worked four years for the U.S. company, and two years in Ontario for the Canadian subsidiary, was not entitled to severance pay because he had not worked in Ontario for more than five years. The court held that the provision in the Act was directed to Ontario based employment. Similar rulings have been made in other cases. [Citations omitted.]
However, in a ruling released in April 2014, Paquette c. Quadraspec Inc., 2014 ONCS 2431 (CanLII), the Honourable Justice Paul Kane rejected Justice Corrick's reasoning and held that an employer's entire payroll had to be considered. For more on that decision, have a look at the post The Requirement to Pay Severance in Ontario - The Decision in Paquette c. Quadraspec Inc., 2014 ONCS 2431