### Question
What does base calendar year mean?


### Answer
**Base calendar year** has the following meaning in *26 U.S.C. § 42*:

> the calendar year with or within which the 1st taxable year of the credit period ends

#### Citation:
  - *26 U.S.C. § 42*
  - Heading: **Subtitle A-Income Taxes > CHAPTER 1-NORMAL TAXES AND SURTAXES > Subchapter A-Determination of Tax Liability > PART IV-CREDITS AGAINST TAX > Subpart D-Business Related Credits**

