Moody’s Investors Service Inc. has affirmed the ratings of Manulife Financial Corp.’s primary life insurance operating company, The Manufacturers Life Insurance Co., as well as the ratings of John Hancock Life Insurance Co. The outlook for all ratings is stable.

The announcement follows the completion Wednesday of the merger between Manulife and John Hancock.

Moody’s has also upgraded the insurance financial strength rating of Maritime Life, John Hancock’ Canadian subsidiary, to Aa3 from A1. The outlook for its rating is now stable.

Dominion Bond Rating Service Ltd. said Wednesday it has upgraded its credit ratings on Maritime Life and John Hancock Financial Services Inc., following their acquisition by Manulife.