Hanover, N.H.-based machinery maker Hypertherm Inc. was ranked No. 6 in the list of the top "50 Best Small & Medium Companies to Work for in America."

The list is compiled by the Society for Human Resource Management and was announced during the society's 58th annual conference June 26 in Washington, D.C.

This is the third year of the list, which ranks the top 25 small and top 25 medium companies in America as selected by the Great Place to Work Institute. The companies range in size from 50 to 999 employees. The results are based on randomly distributed employee opinion surveys.

"Small- and medium-sized companies make up the majority of the American economy and work force," said Susan R. Meisinger, president and CEO of the Society for Human Resource Management. "These winning organizations demonstrate that making effective use of the work force is key to their success and they must be recognized for their accomplishments."