This is what winning looks like.... Delta Regains Investment Grade After Anderson Leads Comeback Delta Air Lines Inc. achieved its longstanding goal of regaining investment-grade credit, following through on a priority of retiring Chief Executive Officer Richard Anderson. Moody’s Investors Service raised the airline’s senior unsecured debt rating to Baa3, the lowest investment-quality level and higher than the junk grades of rival carriers American Airlines Group Inc. and United Continental Holdings Inc. Discounter Southwest Airlines Co. is already investment grade. The upgrade Thursday should lower Delta’s borrowing costs and enhance its ability to sell debt that isn’t backed by aircraft or other collateral, said Moody’s analyst Jonathan Root. The accomplishment gives a boost to Anderson, who will retire in May and repeatedly has talked of wanting to change investors’ poor perception of airlines. “It’s been a long time coming,” said Vicki Bryan, senior bond analyst at Gimme Credit. “Delta’s had the credit quality in my view that was more than ample to meet investment grade.” The upgrade validated Delta’s performance and financial strategy, the Atlanta-based airline said in a statement. Shares rose 0.3 percent to $42.83 at 11:52 a.m. in New York.