AMC Entertainment Holdings Inc AMC.N surged 50.4% as individual traders on social media forums were unfazed by a hedge fund flipping its stake in AMC, calling it overvalued. By Medha Singh and Shashank Nayar June 2 (Reuters) - Wall Street's main indexes firmed ahead of closely watched economic data this week as investors grappled with concerns over inflation and the latest leg of a surge in so-called "meme stocks". Investors are closely tracking the labor market's recovery after an unexpected slowdown in jobs growth in April fanned inflation worries.