Canadian life insurance stocks have been on a tear: Manulife Financial Corp., Sun Life Financial Inc., and Industrial Alliance Insurance and Financial Services Inc. have all jumped by 30 per cent or more since the start of 2012, while Great-West Lifeco Inc. is the laggard with a robust 26 per cent return. But as insurers prepare to report fourth-quarter earnings next month, investors should beware: There is a growing amount of speculation built into their stock prices about the future direction of long-term interest rates. If interest rates don’t start rising quickly, Canadian insurers could be in for a big correction.