Comment by greatwave1

"In 43 metropolitan areas and 160 smaller markets, Walmart captures 50 percent or more of grocery sales. In 38 of these regions, Walmart’s share of the grocery market is 70 percent or more."

https://ilsr.org/walmarts-monopolization-of-local-grocery-ma...

I could list off every one of these areas, but would probably run into the character count limit