Message : Required fields TORONTO (Reuters) - Manulife Financial Corp MFC.TO shares dropped by the most since June on Thursday after Canada's biggest life insurer posted a large fall in reported net income the previous day driven by the negative impact of a steepening yield curve. The 80-basis-point steepening in the yield curve was "unusual," and the most since the company instituted its hedging program in 2012, Chief Financial Officer Phil Witherington said on an analyst call. But this could be reversed if interest rates rise, he said. "If the steepening of the yield curve reverses, and rates at shorter end increase, giving rise to a flattening, the direct market impact charges we've seen in the first quarter would reverse," he said.