RATINGS CHANGES

Ambac (AMBC) - Get Report was downgraded to sell from neutral at MKM Partners. $10 price target. The company is facing increased regulatory scrutiny, MKM said. 

Bristol-Myers Squibb (BMY) - Get Report was upgraded to buy at Jefferies. $69 price target. The company has an attractive clinical pipeline, but trades at a discount to its peers, Jefferies said. 

Blackstone (BX) - Get Report was upgraded to buy at TheStreet Ratings. You can view the full analysis from the report here: BX.

Dexcom (DXCM) - Get Report was upgraded to outperform from perform at Oppenheimer. $84 price target. The company is focused on big, long-term opportunities, Oppenheimer said. 

Merck (MRK) - Get Report was downgraded to underperform at Jefferies. $48 price target. Earnings estimates are below consensus, as Keytruda should continue to face pressure, Jefferies said. 

Realogy (RLGY) - Get Report was upgraded to outperform from neutral at Wedbush. $32 price target. The company is trading at a depressed valuation and is leveraged to rising existing home sales, Wedbush said. 

United Technologies was upgraded to outperform from neutral at Credit Suisse. $125 price target. Profit margin and earnings momentum are near a bottom, Credit Suisse said. 

Williams (WMB) - Get Report was upgraded to overweight from equal-weight at Morgan Stanley. $35 price target. Business has stabilized and management should now focus on the cost of capital, Morgan Stanley said. 

This article was written by a staff member of TheStreet.