Last month, U.S. President Donald Trump signed a $1.5 trillion tax overhaul into law, which slashed the corporate rate from 35 percent to 21 percent.

While most U.S. bank executives expect a long-term boost from the new tax code, the big lenders will first need to book multi-billion-dollar charges to adjust deferred tax assets and liabilities for the lower tax rate and also take charges related to other tax changes.

Sun Life said the estimated $200 million charge reflects the impact of the tax reform on deferred tax assets and liabilities as well as a charge on estimated repatriation of foreign earnings, among other things.

The insurer, which reports results on Feb. 14, also expects the tax expense included in its underlying net income for 2018 to decrease by about $130 million.

(Reporting by Nivedita Bhattacharjee; Editing by Savio D'Souza)