Boeing's bonds were rated AA- by S&P. Would you consider these bonds investment grade or junk bonds?

MINI CASE 

Sam Struthers and Shawna Tibbs are vice-presidents of Mutual of Seattle Insurance Company and co-directors of the company's pension fund management division. A major new client, the Northwestern Municipal Alliance, has requested that Mutual of Seattle present an investment seminar to the mayors of the represented cities, and Struthers and Tibbs, who will make the actual presentation, have asked you to help them by answering the following questions. Because the Boeing Company operates in one of the league's cities, you are to work Boeing into the presentation.