This series, brought to you by Yahoo! Finance, looks at which upgrades and downgrades make sense, and which ones investors should act on. Today, our headlines feature a new buy rating for Bloomin' Brands Inc (NASDAQ: BLMN ), and an upgrade for Ann Inc (NYSE: ANN ). But the news isn't all good, so before we get to those two, let's take a look at why one analyst thinks that… Arcelor Mittal is smelting down The day opened on a sour note for shareholders of world's-largest steel maker ArcelorMittal (ADR) (NYSE: MT ), which this morning got hit with a downgrade to "underweight" by investment banker Morgan Stanley. Although down 15% over the past year, ArcelorMittal (ADR) (NYSE: MT ) shares have gained 9% since their lows earlier this month. Morgan Stanley, however, believes these games are "unsustainable," and that the shares are due to fall again. I agree. Unprofitable, and trading for 35 times trailing free cash flow, ArcelorMittal (ADR) (NYSE: MT ) shares look richly valued today.