Twitter Inc 's stock was trading lower by nearly 5 percent after the company was on the receiving end of two negative reports by Wall Street analysts.Evercore ISI: More Risk Than Reward, Downgrading To SellAccording to a team of analysts at Evercore ISI, Twitter is certainly a "very exciting" social media platform, but the stock's valuation should be of concern for investors.Specifically, Twitter's stock has "more risk than reward," especially when considering similarly scaled social media peers are showing accelerating (Snapchat) growth or steady (Instagram) growth.Full story