Investors in a large disability insurer have been benefiting today from speculation about a possible acquisition.

Reuters is reporting that some securities analysts believe that UnumProvident Corp., Chattanooga, Tenn., may be about to get an acquisition offer from Sun Life Financial Inc., Toronto.

Anonymous participants on Internet message boards that focus on UnumProvident have speculated that Great-West Life & Annuity Insurance Company, Greenwood Village, Colo., a unit of Power Corp. of America, Montreal, might be another possible buyer.

Investors welcomed the rumors by pushing the price of UnumProvident shares to $22.11 at 1:46 p.m., up 11% for the day.

Representatives for UnumProvident and Sun Life declined to comment on the rumors, and representatives for Great-West were not immediately available for comment.