The life insurance market in the United States is both massive and highly competitive. In 2014, roughly 180 million Americans carried some form of life insurance. In the same year, more than 900 life insurers reported a total of nearly $147 billion worth of direct premiums written across the country.

The single biggest life insurer in the U.S., MetLife Inc., reported $11.3 billion in written premiums and market share of nearly 7.7%. Three other insurers, Northwestern Mutual, New York Life and Prudential Financial, Inc., managed to capture more than 5% of the market and more than $7 billion in written premiums apiece. Even the forty-ninth ranked company, Allstate Insurance, reported more than $711 million in written premiums on market share of only 0.5%.

MetLife

MetLife, Inc. (NYSE: MET) is the biggest life insurance company in the U.S. as of 2015. It reported nearly $11.3 billion in written premiums in the domestic market, which amounts to a market share of 7.66%. MetLife wrote additional life insurance premiums in foreign markets that amounted to just under $1 billion, making it one of the few companies in this list with a substantial life insurance business abroad.

MetLife ranks among the world's largest companies in any industry, reporting consolidated revenue of $73.3 billion in 2014. The company offers a variety of insurance products, annuities, employee benefits programs and asset management services. It has operations in nearly 50 countries and counts more than 100 million customers worldwide. MetLife has a market capitalization of about $56 billion.

Northwestern Mutual

Northwestern Mutual Life Insurance Company reported more than $9.5 billion in written life insurance premiums in 2014, giving it nearly 6.5% of the American market. In addition to its life insurance and other insurance products, the company offers annuities, investment products and financial planning services. Northwestern Mutual reported about $26.7 billion in consolidated revenue in 2014.

As a mutual insurance company, Northwestern Mutual is managed for the benefit of policyholders rather than stockholders. Policyholder dividends amounted to $5.5 billion in 2014, nearly $5 billion of which was paid out to life insurance policyholders. Of those dividend payments, about 75% was used to purchase further Northwestern Mutual insurance protection.

New York Life

New York Life Insurance Company wrote about $8.2 billion in domestic life insurance premiums in 2014, which amounts to approximately 5.6% of the market. Apart from its life insurance business, New York Life also sells long-term care insurance, annuities and mutual funds, and it operates a growing investment management business.

New York Life is a mutual insurance company, and it is not publicly traded. It ranked as the largest mutual life insurance company in the country as measured by consolidated revenue, which amounted to about $38.7 billion in 2014. Policyholder dividends amounted to nearly $1.45 billion in the same year, of which about $1.4 billion was paid to individual life insurance policyholders.

Prudential

Prudential Financial, Inc. (NYSE: PRU) is the fourth-biggest life insurance company in the U.S. It is a publicly traded financial services conglomerate offering insurance products, annuities, mutual funds, investment management services and other products. The company operates in 43 countries in North and South America, Europe and Asia.

Prudential's life insurance business was responsible for more than $7.7 billion in direct written premiums in the U.S. in 2014, which was good for nearly 5.3% of the market. The company's worldwide consolidated revenue was $49.6 billion in the same year. It has a market capitalization of $36.4 billion.

Lincoln National

Lincoln National Corp. (NYSE: LNC) is a financial services company offering life insurance products, long-term care insurance products, annuities and retirement plan services to 17 million American customers. It does not operate outside the U.S. The company and its subsidiaries are marketed to consumers under the Lincoln Financial Group brand.

Lincoln National reported $6.44 billion in written life insurance premiums in 2014, which amounts to about 4.4% of the total market share. Its consolidated revenue amounted to more than $13.7 billion on the year, an increase of more than 13% over the prior year. Lincoln National has a market capitalization of $12.7 billion.

MassMutual

Massachusetts Mutual Life Insurance Company, known as MassMutual, is the sixth-biggest life insurer in the U.S. and the third mutual company on this list. It reported nearly $5.6 billion in direct written life insurance premiums in 2014, giving it a market share of 3.8%. The company also offers annuities, long-term care and disability income insurance, and wealth management and investment services. MassMutual reported consolidated revenue of about $26.4 billion in 2014. It paid eligible policyholders dividends of more than $1.5 billion in the same year, an increase of 5% over the previous year.

John Hancock

John Hancock Financial has operated as a wholly owned subsidiary of the Canadian insurance giant, Manulife Financial Corp. (NYSE: MFC), since the companies merged in 2004. In addition to life insurance policies, the company offers long-term care insurance policies, mutual funds, and retirement and college savings plans. It remains headquartered in Boston, Massachusetts, as it has been for the last 150 years.

John Hancock wrote $4.71 billion in written life insurance premiums in 2014, which amounts to 3.2% of the U.S. market. Manulife Financial reported $28.9 billion in total revenue for John Hancock operations in the U.S. in 2014. Manulife Financial has a market capitalization of $32.4 billion.

Transamerica

While Transamerica Corporation was established in San Francisco in 1930, it has operated as a wholly owned subsidiary of the Dutch life insurance company, Aegon N.V, since its takeover in 1999. In addition to life insurance products, Transamerica offers long-term care insurance, annuities, mutual funds and pension plans.

Transamerica was responsible for $4.38 billion in written life insurance premiums in the U.S. in 2014, amounting to market share of about 3%. Aegon reported total revenue of nearly $17.5 billion for its North American and Latin American business unit, which is dominated by the Transunion operations in the U.S. Aegon has a market capitalization of about $13 billion.

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