For the second year in a row, Portland-based insurer The MEMIC Group will issue an annual dividend of $18 million in November to employers who buy workers’ compensation insurance from the company.

The dividend announced Thursday matches MEMIC’s previous high in 2014 and represents more than 14 percent of the premiums paid by policyholders in 2012, the year upon which the dividend is based. The payments, which range up to $200,000, will be issued to more than 17,000 policy-holding companies in Maine. The individual amounts depend on the premiums each company paid in 2012.

MEMIC, which stands for Maine Employers’ Mutual Insurance Co., insures more than 20,000 employers and an estimated 300,000 employees in 46 states and the District of Columbia.

Although annual dividends paid out by MEMIC have trended upward since 2009, company officials said the continuation of low interest rates is making it more difficult to generate such high returns. Insurance companies invest customers’ premiums in low-risk securities, primarily bonds, to increase the value of their assets.

“Because the return on invested assets has dwindled across the industry in recent years, we’ll have to continue to work together with policyholders to improve workplace safety to drive future dividends,” MEMIC President and CEO John T. Leonard said in a news release.

MEMIC said it has now issued dividend payments of about $200 million to policyholders since 1998.