What is the minimum number of pieces required in a 5-digit sack for a USPS Marketing Mail flats mailing?

The minimum number of pieces required in a 5-digit sack for a USPS Marketing Mail flats mailing is indeed 125 pieces. This requirement ensures that mailings are economically feasible for the USPS to process and deliver. By setting a minimum quantity, the USPS can streamline operations and manage logistics more effectively, allowing for a more efficient mail flow.

Choosing a higher minimum number, such as 150 or 200 pieces, while potentially common in other contexts, does not align with the established guidelines for marketing mail flats, which aim to accommodate both small and large mailers. The figure of 125 pieces specifically enables smaller businesses or organizations to participate in marketing mail using the 5-digit presort, allowing them access to bulk mailing discounts and promoting broader engagement with postal services.