All companies with foreign national employees should have a robust immigration policy to ensure, and demonstrate, their commitment to compliance with the law.
Governments worldwide are placing responsibility for immigration compliance firmly at the door of the employer— not the employee. Employers found to be out of compliance, or who simply can't prove compliance, can be fined, barred from hiring foreign national employees, or even closed down. The U.S. Foreign Corrupt Practices Act (FCPA), and the UK Bribery Act 2010 make U.S. and UK companies (plus companies with branch offices in the UK) legally liable for corrupt activities by subsidiaries or suppliers outside the U.S./UK.
Your immigration policy needs to be appropriate for your company size and structure. It should be realistic as it must be adhered to. Depending on the jurisdictions in which your companies operate, your policy may need to contain certain specific details.