Its market value jumped to $21 billion, overtaking $18 billion of GameStop GME.N, which was at the heart of a retail trading frenzy earlier this year. 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.