It is legally possible for an employer to provide a global benefits package, and many employers decide to do so because it is administratively more efficient than offering localvariations and, crucially for a global workforce, ensures parity of treatment across the organisation.
A global package is attractive for employers with a mobile workforce because it saves having to offer new rewards or amend existing benefit packages each time the employee is assigned to a new location. It is important, however, that the benefits offered meet any local minimum statutory or regulatory requirements, and are adapted as necessary to ensure they are 
compliant. Furthermore, an employer considering a global package needs to ensure that benefits offered via any third-party providers apply equally in all relevant jurisdictions, for example, medical benefits and insurance policies sometimes contain exclusions for certain countries.
Another important consideration is data protection and the ability to transfer employee data to a central team and/or third party which may be administering the global benefits. There are likely to be local restrictions on the ability to transfer data that need to be checked and complied with and, in some cases, express employee consent will be required.
The ability and ease with which new benefits can be implemented and existing benefits revised or withdrawn should also be reviewed. In some countries, this will be harder than others and consultation with works councils and/or other employee bodies may be required. In some countries, consent to make changes will be needed.
Finally, an employer will want to ensure that the cost of offering any benefit in any particular jurisdiction is economic, from a tax as well as cost perspective, both for the employer and the employee. There is little point in providing a benefit if the burden of doing so outweighs the benefit provided.
Sarah Henchoz is partner in the employment team, and Paul McCarthy is partner in corporate incentives at law firm Allen and Overy