The U.S. subsidiary of Canadian insurer Great-West Lifeco Inc. has closed a multi-billion dollar deal to buy the U.S. retirement business of Prudential Financial Inc.

The $4.45-billion acquisition expands the Winnipeg-based company's presence in the lucrative U.S. retirement market through its Denver, Colo., subsidiary Empower Retirement.

Great-West Life says the deal increases Empower's base to over 16.6 million participants, 71,000 workplace savings plans and about US$1.4 trillion in assets under administration.

Paul Mahon, president and CEO of Great-West Life, says the strategic transaction has advanced the company's value-creation priorities and accelerated growth.

He says Empower and its customers will benefit from significant added scale and capabilities, solidifying its leadership position in the world's largest retirement market.

The company says Empower's contribution to Great-West Life's earnings is expected to grow to 30 per cent by the end of 2023.