### Question
How is the "base period T-bill rate" defined?


### Answer
The term **base period T-bill rate** is defined in *26 U.S.C. § 995* as follows -

> the annual rate of interest determined by the Secretary to be equivalent to the average of the 1-year constant maturity Treasury yields, as published by the Board of Governors of the Federal Reserve System, for the 1-year period ending on September 30 of the calendar year ending with (or of the most recent calendar year ending before) the close of the taxable year of the shareholder

#### Citation:
  - *26 U.S.C. § 995*
  - Heading: **Subtitle A-Income Taxes > CHAPTER 1-NORMAL TAXES AND SURTAXES > Subchapter N-Tax Based on Income From Sources Within or Without the United States > PART IV-DOMESTIC INTERNATIONAL SALES CORPORATIONS > Subpart B-Treatment of Distributions to Shareholders**

