<p>Previous research found that tax havens stimulate economic growth. However, the related literature does not clearly distinguish between tax havens in sovereign nations (that are mostly for manufacturing corporations) and colonial tax havens (that are mainly for high-income individuals and the service sector). Nowadays, almost a third of the tax havens around the world are colonies. Given that many colonies started as tax havens a long time ago, when there was no data, we evaluated the case of Puerto Rico, the largest economy among them. Puerto Rico became a tax haven mostly for individuals in 2012. We applied both the traditional synthetic control methods and a Bayesian Structural Times Series Model. Both methods yielded similar results. The 2012 policy intervention had a moderately positive effect on output and employment compared to counterfactual levels. We recommend a reform of these policies to exploit their full potential.</p>