### Question
What is the definition of United States tax?


### Answer
The definition of **United States tax** is as follows in *26 CFR § 509.104*:

> the Federal income taxes, including surtaxes and excess profits taxes, and any other income or profits tax of a substantially similar character imposed by the United States after May 24, 1951

#### Citation:
  - *26 CFR § 509.104*
  - Heading: **PART 509—SWITZERLAND**

