Image: 401k © Tom Grill, Corbis

Workers in the private sector were offered a median 401k match of 3% of pay in 2010. But the maximum possible employer contribution is considerably higher for specific groups of workers. Here's a look at which employees are getting the biggest company contributions to their 401k plan.

Employees of credit intermediation firms. Credit intermediation companies generally offer the most generous 401k contributions of any industry -- a median of 5% of pay, according to recently released Bureau of Labor Statistics data for 2010. Employers in this sector include mortgage and loan brokerages, clearinghouse and reserve services, check-cashing services, and other financial institutions that lend funds raised from depositors or credit market borrowing. (How much will your 401k provide? Find out with MSN Money's calculator.)

Protective service workers. Employees in the service sector generally get a below-average 401k match, unless they work in the protective service. Protective service employees in the private sector got a median employer contribution to their 401k of 5% of pay in 2010.

Managers. Management employees in the business and financial industry got a median employer contribution of 4% of pay to their retirement accounts. And those in the 90th percentile had a median of 6% of pay deposited into their 401k as a matching contribution.

Western residents. Workers who live in the Pacific (4% of pay), New England (3.6%) and Middle Atlantic (3.6%) regions get a larger median 401k match than those in the rest of the country (3%).

Insurance carriers. Employees who underwrite or sell annuities and insurance policies received a median 401k contribution of 3.9% of their salary in 2010.

Trade, transportation and utilities workers. The trade, transportation and utilities sectors provided a median 401k match of 3.5% of pay last year.

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Large company employees. Large companies generally provide more generous retirement benefits than smaller businesses. Employees at companies with 500 or more workers received a median 401k contribution of 3.5% of pay, compared with a median of 3% at smaller companies.

The smallest employer contributions to 401k plans were provided by health care and social assistance employers (2% of pay) and the service industry (2.5% of pay) in 2010.

According to the Bureau of Labor Statistics, 49% of employers that offer 401k's do not offer any match.