In other words, while the expatriate employee is on foreign assignment, the employee will pay approximately the same amount of income and social security taxes (referred to as "stay-at-home" or "hypothetical" tax liability) as they would have paid had they remained in the U.S., or their home country, and only earned the items of compensation that they would normally earn such as base wages and bonuses. The company pays any taxes that exceed the expatriate's hypothetical tax liability. Companies also implement tax equalization policies so that expatriate employees are treated fairly and consistently throughout the world