Amazon is already worth more than a monopoly.

NEW YORK, Sept 19, 10:14 am (Reuters Breakingviews) - Amazon.com  says the idea it’s illegally squeezing its merchants is “exactly backwards." California Attorney General Rob Bonta last week accused the company started and chaired by Jeff Bezos of violating antitrust law, in the $1.3 trillion e-commerce giant’s biggest legal challenge yet. Whether California prevails or not, investors have already granted Amazon a market valuation fit for a monopoly.

The lawsuit filed on Sept. 14 blames Amazon for punishing retailers who list products for a cheaper price elsewhere, like Walmart  or Target, saying this effectively sets a price floor for goods. Amazon, meanwhile, argues that forcing it to showcase products at higher prices would be antithetical to antitrust regulatory goals. That’s valid in that antitrust has tended to focus on consumer prices.

Amazon’s dominance in e-commerce may attract foes, but it also confers a premium stock price. One way to value the retail part of Amazon is to strip away the more profitable cloud business, Amazon Web Services. Valued at the same 6 times revenue as Oracle , that division would have an enterprise value of $370 billion, leaving the retail business at close to $1 trillion.

Such a valuation is more than double Amazon’s retail sales last year. But there’s another way of thinking about it. Rivals Walmart and Target both trade at under 0.9 times revenue. Start with that as a reasonable multiple for Amazon once it reaches maturity, and it’s as if investors are saying that the company can generate upwards of $1.1 trillion in sales. If two-thirds of that comes from North America, it’s equivalent to Amazon capturing 75% of the U.S. e-commerce market.

Amazon’s revenue is nowhere near there yet. The premium valuation, though, is an implicit reflection of the company’s potential market power. That’s not much use for Amazon’s political detractors as they try to hang lawsuits on what the company does now rather than what it might do later. But in the longer run, either California has it exactly backwards, or Amazon’s shareholders do.

California filed a lawsuit against Amazon.com on Sept. 14, alleging the company violated antitrust law by requiring merchants to enter into agreements that penalize them if they sell their wares more cheaply on other websites. California Attorney General Rob Bonta said Amazon's rules keep prices artificially high. “Merchants must agree not to offer lower prices elsewhere — including competing sites like Walmart, Target, eBay, and, in some cases, even on their own websites,” Bonta said in a statement.

Amazon argued that the state had it “exactly backwards” in an emailed statement. It added that “the relief the AG seeks would force Amazon to feature higher prices to customers, oddly going against core objectives of antitrust law.”