By Larry Gellar Let’s take a look at five of the latest analyst upgrades. Blackstone (BX) and AIG are benefiting from certain unique economic trends. Meanwhile, Chipotle (CMG), Safeway (SWY), and Express Scripts (ESRX) are using new business models to fuel growth. Let’s see what specifically has been happening with these five stocks: William upgraded Chipotle Mexican Grill, Inc. to Outperform, noting that the company has had good momentum with sales. In fact, CMG stock has been steadily rising since December. Trading for less than $320 at that time, the stock price is now well over $350. That has some investors thinking that the stock is now overvalued, and for good reason. While Chipotle may see tremendous growth in the future, the stock price already reflects that. Chipotle may be able to outdo expectations if the new ShopHouse brand works out well, but it may have made even more sense for Chipotle to just focus on the Chipotle restaurants for the time being. Maybe Chipotle can eventually spin out ShopHouse the way that McDonald’s (MCD) spun out Chipotle. Value metrics for Chipotle are currently a price-to-earnings ratio of 55.24, price/earnings to growth of 2.54, and price to sales of 5.05,…


