Firing from the hip here having previously worked on antitrust issues, I don’t think this is going to get even close to tripping horizontal antitrust concerns nationwide.

There may be some geographies regulators ask them to divest stores in because the combined company would have too much market share, but it still wouldn’t even be the largest grocery retailer in the US. It’s hard to claim a merger should be blocked on antitrust concerns when a larger company already exists. Walmart, CostCo and even Target are scaled competitors, and then there’s tons of niche/regional players in the space like Aldi, Sprouts, Trader Joe’s, Whole Foods, HEB, Publix, Dollar General etc.

As an aside, I’m not generally a fan of consolidation. This is just how I think current antitrust laws will view this.