What happened Shares of AMC Entertainment Holdings (NYSE: AMC), GameStop (NYSE: GME), and Sundial Growers (NASDAQ: SNDL) were all down in midday trading Friday despite the market indexes continuing their bullish run higher. The movie theater operator was down 3.5% heading toward noon, while the video game retailer was almost at breakeven, and the marijuana producer was off 2.1%. The Dow Jones Industrial Average was advancing 225 points for a 0.6% gain. Image source: Getty Images. So what There wasn't any news directly related to any of these stocks, but that hasn't been necessary to drive them higher or lower, as chatter in internet chat rooms has more often than not been the deciding factor. Too often traders discuss hedge funds, dark pools, and short-sellers that need to be defended against rather than the merits of the companies' specific business model. Too often the stocks are the ones holding the weak hands, regardless of who is backing them. Now what None of these companies are going out of business, at least not anytime soon, and each feasibly has a plan of attack to recover its foundational footing and grow again. Because AMC, GameStop, and Sundial all still trade at inflated valuations in relation to where they were prior to the trading frenzy at the start of the year, it means there's probably more downside risk to the stocks than further upside potential. Investors would be wise to block out the noise and once again return to the fundamentals of a company to determine its worth as an investment. 10 stocks we like better than AMC Entertainment HoldingsWhen our award-winning analyst team has a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* They just revealed what they believe are the ten best stocks for investors to buy right now... and AMC Entertainment Holdings wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of June 7, 2021 Rich Duprey has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.Source