The company, which has operations in Canada, the United States and Asia, also booked a C$285 million ($214.08 million) net charge in the third quarter after undertaking an annual actuarial review.

A slump in oil prices over the past year has hit companies exposed to the energy industry. The Canadian energy sector in the Toronto composite index has shed about 32 percent of its value during that time.

Higher volatility in equity markets, which was sparked this summer by uncertainty about the pace of China's economic growth, has put further pressure on insurance companies.

"Oil and gas over the cycle has been a very good investment category for us, but it does bring some volatility,” Manulife Chief Financial Officer Steve Roder said in an interview. "So right now, we're just experiencing some of that volatility."

He termed the volatility “unfortunate noise," but said Manulife remained a long-term investor in the energy industry.

Oil and gas account for less than 1 percent of Manulife's total asset portfolio.

The company's net income fell to C$622 million, or 30 Canadian cents a share, in the third quarter, from C$1.1 billion, or 57 Canadian cents, a year earlier. Core earnings, which exclude the impact of short-term factors such as interest rate fluctuations, rose to 43 Canadian cents per share from 39 cents. Analysts on average expected 45 Canadian cents, according to Thomson Reuters I/B/E/S.

In Asia, where Manulife has been expanding in recent years, core earnings jumped 30 percent. Double-digit growth in Japan and Hong Kong helped boost insurance sales.

Manulife's assets under management and administration rose 19 percent to C$888 billion.

The stock, which is down about 2.2 percent since the start of the year, slipped 2.1 percent on the Toronto Stock Exchange.

($1 = 1.3313 Canadian dollars)

(Editing by W Simon, Lisa Von Ahn and Paul Simao)

By John Tilak