MetLife Inc. expects operating earnings to grow more than a third next year as the largest U.S. life insurer benefits from its blockbuster acquisition of global life insurer Alico.

The company expects operating earnings to decline across its U.S. business lines in 2011, but that will be more than offset by gains from Alico, which MetLife acquired from American International Group Inc. in November.

The Alico deal radically reshaped MetLife's profile and doubled what international operations contribute to the company's overall earnings. MetLife paid $16.2 billion in cash and stock for Alico, making AIG its largest shareholder.

Alico has major operations in Japan, where the economy has been weak, but MetLife says it sees some business momentum, and has faster growing operations in Latin America.

MetLife said Monday that it expected 2011 operating earnings, excluding investment gains and losses, of $5.1 billion to $5.5 billion, or $4.75 to $5.15 per share. Analysts polled by Thomson Reuters I/B/E/S on average expected earnings of $5.03 per share.

In a slide presentation filed with securities regulators ahead of its investor day, MetLife said its largest segments in 2011 by earnings will be U.S. corporate benefits, international life and international accident and health. The three together will account for 46 percent of operating results.

The company forecast slow economic growth in both the United States and Japan next year, with continued low interest rates domestically and disinflation or deflation in Japan.

"The economy's not performing the way any of us would have liked at this point in time in terms of the recovery," Steve Kandarian, MetLife's chief investment officer, said in a presentation at the investor meeting.

The low interest rate environment in particular has become a huge concern for U.S. insurers given its impact on their investment portfolios.

MetLife projected 10-year rates would actually fall from current levels through the end of March 2011 before starting to rebound.

For this year, MetLife expects operating earnings of $4.26 to $4.36 per share, while analysts expected $4.28.

Based on the midpoint of the ranges, the company expects a 38 percent earnings increase for next year.

For the current quarter, MetLife forecast operating earnings of $1.04 to $1.14 per share, while analysts expected $1.04.

The company also said it anticipated an improved operating return on equity of 11 percent for 2011.

MetLife shares rose 0.6 percent to $40.40 in premarket trading from a $40.14 close on Friday.

MetLife shares trade at a ratio of 1.19 times the company's book value, against a sector median of 0.94, according to Thomson Reuters data.