Although the U$.$S$.$ ready to eat $($RTE$)$ cold cereal market has been losing sales over the last $5$ to $8$ years or so$,$ it is still very profitable. In $2018,$ the industry earned about $$8\mathrm{.}5$ billion in sales. The industry is highly oligopolistic in that just four $(4)$ firms: General Mills $($GM$),$ Kellogg $($K$),$ Post Holdings $($PH$),$ and Quaker Foods $($PepsiCo$)($Q$)$ account for $$7\mathrm{.}5$ billion of those sales.