>Second, Delaware’s tax system gives businesses several ways to legally minimize their tax bills. Companies that are incorporated in Delaware but do business in other states don’t have to pay state corporate income tax to Delaware. Some groups accuse Delaware of being a tax haven because the “Delaware loophole” allows companies to declare certain types of revenue in Delaware rather than in the state where the business actually occurred. Delaware also doesn’t tax profits on royalty payments, trademarks, or copyrights.

https://www.mentalfloss.com/article/76951/why-are-so-many-us...