S&P said the ratings were put on "CreditWatch with positive implications."
"The action, in particular, is based on improving profitability, aided by solid demand for commercial airplanes from a recovering global airline industry, substantial cash flow and expectations that management will continue to pursue a balanced capital allocations to achieve stronger credit protection," the agency said.
Earlier Wednesday, Boeing, which has about $10 billion of consolidated debt outstanding, reported a 31 percent drop in third-quarter earnings, hurt by a hefty charge to end a loss-making service.
Credit ratings predict the likelihood of default and affect the terms under which companies can borrow money. Watch lists indicate that the agency expects to make a change to a company's ratings.
"If long-term ratings are raised, Standard & Poor's expects to raise the corporate credit rating to 'A+' from 'A,'" the agency said of Boeing. S&P did not put the company's short-term debt on the watch list. An 'A' rating means the debt is considered medium grade investment quality, with 'AAA' being the highest grade on the S&P scale.
Boeing shares fell $2.51, or 3 percent, to $80.99 in recent trading on the New York Stock Exchange. Analysts said investors were reacting to an increase in research and development spending that could indicate cost overruns at Boeing's flagship 787 Dreamliner project.
