601.102—Classification of taxes collected by the Internal Revenue Service.
(a) Principal divisions.
Internal revenue taxes fall generally into the following principal divisions:
(b) Assessed taxes.
Taxes collected principally by assessment fall into the following two main classes:
(i)
Income and profits taxes imposed by Chapters 1 and 2 of the 1939 Code and taxes imposed by subtitle A of the 1954 Code, relating to income taxes.
(2)
Taxes not within the jurisdiction of the U.S. Tax Court. Taxes not imposed by Chapter 1, 2, 3, or 4 of the 1939 Code or Subtitle A or Chapter 11 or 12 of the 1954 Code are within this class, such as:
(3)
The difference between these two main classes is that only taxes described in subparagraph (1) of this paragraph, i.e., those within the jurisdiction of the Tax Court, may be contested before an independent tribunal prior to payment. Taxes of both classes may be contested by first making payment, filing claim for refund, and then bringing suit to recover if the claim is disallowed or no decision is rendered thereon within six months.