Singapore is the safest nation to do business, according to the Pinkerton Risk Index Report.

The report ranked Switzerland as the second-safest country. The United States ranked seventh.

At the other end of the scale, Chad has the highest overall risk, followed by Zimbabwe and Guinea, according to the index, which uses data based on factors including natural disasters, disease, terrorism, social unrest and economic problems.

Pinkerton said its report would take into account 83 different variables to help companies make decisions on relocations, expansions, investment and business travel.

The report could also help insurers determine risk for providing coverage around the world.

Pinkerton President Jack Zahran said terrorist attacks and natural disasters were becoming more frequent, potentially causing widespread disruption to supply chains.