Geopolitical volatility is causing rapidly changing sanctions regimes, but diverging rules in different jurisdictions create enforcement gaps that are exploited by sanctioned individuals and entities – and the routes used to evade sanctions are constantly developing. Meanwhile, companies that are unwary or ill-informed risk high penalties.

President Donald Trump’s use of sanctions to pursue political and economic aims is escalating volatility. Military action in Venezuela and ongoing pressure on Russia and Iran are the main drivers, but he recently threatened to impose sanctions on European allies who resisted his claims to Greenland.

Ruth Prickett graduated from Cambridge University with a BA hons in History and has specialized in business and finance journalism for the past 20 years. She was editor of Financial Management, the magazine...