15. C&S Wholesale Grocers, Inc.
> Revenue: $25.9 billion
> Number of employees: 13,200
>Headquarters: Keene, New Hampshire
> Industry: Food Distributer

C&S Wholesale Grocers is the largest grocery wholesaler in the United States, according to the company. The company operates 50 locations across 15 states, serving about 5,000 grocery stores and other customers. The company was founded in 1918 by Israel Cohen and Abraham Siegel in Worcester, Massachusetts. Rick Cohen, current CEO, is the third generation Cohen to lead the company.

14. Massachusetts Mutual Life Insurance Company
> Revenue: $26.4 billion
> Number of employees: 6,800
>Headquarters: Springfield, Massachusetts
> Industry: Insurance

Massachusetts Mutual is one of several insurance companies reporting the 20 highest private company revenues. Mutual insurance companies are owned by their policyholders, and so are private by definition. While the company does not have shareholders, its policyholders are entitled to vote as members of the Board of Directors, and in some cases eligible to receive dividend payments. Massachusetts Mutual is also quite old, founded May 15, 1851.

ALSO READ: Countries Spending the Most on War

13. Northwestern Mutual Life Insurance Company
> Revenue: $26.707 billion
> Number of employees: 5,500
>Headquarters: Milwaukee, Wisconsin
> Industry: Insurance

Like several of the largest private companies, Northwest Mutual is a very old company, founded in 1857. The company has over 330 offices in the United States and serves over four million clients. While the company specializes in life insurance, it offers a broad array of insurance products. The company also offers financial services to its clients, including brokerage services and retirement products.

12. Carlson Wagonlit Travel Inc.
> Revenue: $27.3 billion
> Number of employees: 20,000
>Headquarters: Minneapolis, Minnesota
> Industry: Travel Agency

Carlson Wagonlit is one of the world’s largest travel management companies, according to the company. It operates in 150 countries and generates more than $27 billion in revenue. The company was formed through a 1994 merger of two large travel agencies, Carlson Travel Network and Wagonlit Travel. The company’s oldest component dates back to 1888, when the Ask Mr. Foster travel agency was founded in St. Augustine Florida, the oldest city in the continental United States.

ALSO READ: The Most Democratic County in Each State

11. Ernst & Young LLP
> Revenue: $27.4 billion
> Number of employees: 190,000
>Headquarters: New York, New York
> Industry: Accounting Services

Ernst & Young is one of the biggest accounting firms in the nation. It is one of the Big Four accounting firms in the country along with KPMG, Deloitte, and PricewaterhouseCoopers. The company operates on a global scale, with more than 700 offices in 150 countries. The company became one of the largest accounting firms in part due to mergers and acquisitions of smaller accounting firms. Today’s Ernst & Young is the product of a 1989 merger between Arthur Young and Ernst & Whinney. The oldest component of the company dates back to the founding of the English firm Harding & Pullein in 1849. The company is the largest private employer on our list, with 190,000 employees worldwide.