Few companies have the ability to grow by leaps and bounds for decades at a time. Nu Holdings (NU -0.55%) is one of those rare businesses. Yet few Americans may have ever heard of this exciting fintech stock. That's because the digital bank operates exclusively in just three countries: Brazil, Colombia, and Mexico. Willing to look abroad to give your portfolio maximum growth potential? There are two reasons in particular that Nu shares offer compelling "buy it for life" potential right now. 2. Profits shoul ...