What is the fine-grained topic of the following text: On Friday, October 6, 2017, the United States Postal Service® (USPS®) submitted their proposed rate change cases for both the Market Dominant and Competitive product price lists to the Postal Regulatory Commission (PRC), both with an intended effective date of Sunday, January 21, 2018 at 12:01am. Only return the topic.
Proposed rate change cases for USPS Market Dominant and Competitive products in 2017