Task:
Consider the following quote based on the firm Rubbermaid.
Rubbermaid has experienced major increases in the cost of resin (an important raw material... ) and attempted to pass on these costs with large price increases to its customers. Wal-Mart was particularly angered by the large price increases... Wal-Mart refused to stock a number of Rubbermaid products and deleted Rubbermaid's products from its promotional materials... Instead, Wal-Mart featured Sterilite, one of Rubbermaid's prominent new competitors... When Rubbermaid passed on the huge price increases to its customers, the competitors had only small price increases, deciding instead to reduce their profits rather than pass on the full cost of the raw materials.
The quote illustrates three of Porter's five forces. Which three? How does it illustrate each of them?