Standard & Poor's Ratings Services said Thursday that it has raised its credit rating on Comcast Corp. after the cable company agreed to buy the remainder of NBCUniversal it did not already own, for $16.7 billion.

S&P raised the rating to "A-" from "BBB+" and said that the outlook is positive. Both ratings are investment grade.

S&P said it was raising the rating in part because the financing plan for the deal includes only $6.7 billion in new debt. Its previous rating was based on the expectation that Comcast would rely solely on debt to buy the rest of NBCUniversal from General Electric Co.

Comcast already owns 51 percent of NBCUniversal. It plans to finance its purchase of the rest with $11.4 billion of cash on hand, $4 billion in debt owed to GE, $2 billion from its own credit lines and $725 million in preferred stock issued to GE.

Comcast's widely traded Class A shares rose 39 cents, or 1 percent, to $40.52 in afternoon trading.