WalMart only as an example, not a scapegoat this time. Sorry to disappoint. Their stock has dropped from a high around $90/share early this year to a little under $60 now. There are analysts who are blaming WalMart's decision to raise US worker's starting wages to $10 I believe its incremental with that as the ending point, but however it works out it should be a lot less of a hot button than the popular $15/hour movement. Even though WM is one of the largest employers in the country it makes no numeric sense that a company with a ~$200B market cap and almost $500B in annual revenue would lose 1/3 of that market cap because they decided to pay the lowest paid workers in the organization a few extra bucks a week.
I've heard the opposing argument that the valuation is dropping because of a projected drop in future sales as their customer base continues to be squeezed between higher prices (cost of living) and stagnant or falling wages. That, IMO, seems to be the more logical explanation. If true then it seems WalMart would actually be making a calculated investment by paying more now so the customer base can spend more later. A little smaller slice, but of a bigger pie. As much as I'd love to get away from a consumer based economic model, that seems like a pretty reasonable near term approach.