Best Buy and Toys R Us have filed complaints in several states alleging that Walmart Stores deceived consumers in price comparison ads.

The ads aired from late November to mid-December, according to Toys R Us. Sales in the two months account for 20 percent to 40 percent of U.S. retailers’ annual revenue, the National Retail Federation said.

Best Buy lost “tens of thousands of dollars” because of the ads, according to spokeswoman Amy von Walter, who said in an email that the company has filed complaints in Florida, Illinois, Michigan and New Jersey.

Walmart, the world’s largest retailer, followed “all local, state and federal rules and regulations,” Walmart spokesman Steven Restivo said in a statement. “We know competitors don’t like it when we tell customers to compare prices and see for themselves but we think consumers deserve every chance to find value.”

Kathleen Waugh, vice president of corporate communications for Toys R Us, said that Walmart misled customers about pricing on several toys including the Fisher-Price Surprise Kitchen and Table Set, which was advertised for $39.97. Third-party shoppers found the sets were being sold for up to twice that price, according to Toys R Us. Walmart said the in-store and advertised price for the set was correct at $39.97.