### Question
What does base period mean?


### Answer
**Base period** has the following meaning in *APPENDIX U.S.C. § 1173*:

> any annual period beginning July 1, and ending June 30 with respect to which a base period cost is established

#### Citation:
  - *APPENDIX U.S.C. § 1173*
  - Heading: **CHAPTER 24A-MERCHANT MARINE ACT, 1928 > SUBCHAPTER VI-OPERATING-DIFFERENTIAL SUBSIDY**

