Walmart is the largest retailer with both brick-and-mortar stores and a growing internet business. Walmart continues to innovate with its service to shop online and pick up at the store. Walmart has also faced criticism due to its low wages and difficulty for part-time employees to get group health insurance. Many consumers refuse to shop at the store due to their employee policies. Based on this scenario, which criterion for an exchange to occur is missing?

From the question, we are informed that Walmart is a huge retailer but despite that, it has faced criticism as a result of its low wages and difficulty for part-time employees to get group health insurance and that this has led many consumers refusing to shop at the store due to their employee policies.

The criterion for an exchange to occur that is missing here is that "each party is willing to consider the other to be a desirable exchange partner". In this scenario, the customers doesn't see Walmart as a desirable excange partner due to the way they treat their workers therefore an exchange cannot take place.