For multinational companies, political risk refers to the risk that a host country will make political decisions that will prove to have adverse effects on the multinational's profits and/or goals. Adverse political actions can range from very detrimental, such as widespread destruction due to revolution, to those of a more financial nature, such as the creation of laws that prevent the movement of capital.
In general, there are two types of political risk, macro risk and micro risk. Macro risk refers to adverse actions that will affect all foreign firms, such as expropriation or insurrection, whereas micro risk refers to adverse actions that will only affect a certain industrial sector or business, such as corruption and prejudicial actions against companies from foreign countries. All in all, regardless of the type of political risk that a multinational corporation faces, companies usually will end up losing a lot of money if they are unprepared for these adverse situations. For example, after Fidel Castro's government took control of Cuba in 1959, hundreds of millions of dollars worth of American-owned assets and companies were expropriated. Unfortunately, most, if not all, of these American companies had no recourse for getting any of that money back.
So how can multinational companies minimize political risk? There are a couple of measures that can be taken even before an investment is made. The simplest solution is to conduct a little research on the riskiness of a country, either by paying for reports from consultants that specialize in making these assessments or doing a little bit of research yourself, using the many free sources available on the internet (such as the U.S. Department of State's background notes). Then you will have the informed option to not set up operations in countries that are considered to be political risk hot spots.