1. G4S
And last but not least, the behemoth of security companies, the biggest currently in operation, G4S.
As said in the introduction, G4S is the third largest private sector employer” and employed 610,000 people at the end of 2015. They are working in more than 100 countries and, on their website, describe their job as doing “outsourced business processes and facilities in sectors where security and safety risks are considered a strategic threat.” Their career website offers a wide range of jobs across almost all continents. In 2010, G4S was one of the founding members and signed the Global Code of Conduct For Private Security Providers. This code implies that the training provided to their staff is to the highest standard to ensure that their staff knows how to handle all situations.
Those are the biggest private security companies that are hiring and provide a good environment for personal growth and career advancement.