Complex sentence: Nigerian organized crime groups are active in at least 80 countries around the world, including the United States, most notably active in the areas of drug trafficking and fraud, which loses American businesses between $1-2 billion a year.
Split into simpler sentences: Nigerian organized crime groups are active in at least 80 countries around the world, including the United States. Nigerian OC groups are also notorious for fraud, which lose American businesses between $1-2 billion a year.