17. CONCENTRATIONS

For the three months ended March 31, 2017, 24% of revenues were derived from one customer: Digi-Key Electronics in the Power and Electromechanical segment. For the three months ended March 31, 2016, 33% of revenues were derived from two customers: Digi-Key Electronics in the Power and Electromechanical segment at 21% and National Grid in the Energy segment at 12%.

The Company’s major product lines during the first three months of 2017 and 2016 were power and electromechanical products and natural gas infrastructure and high-tech solutions.

At March 31, 2017, of the gross trade accounts receivable of $10.2 million, 26% was due from two customers: National Grid in the Energy segment at 16% and Digi-Key Electronics in the Power and Electromechanical segment at 10%. At December 31, 2016, of the gross trade accounts receivable totaling $9.5 million, 30% was due from three customers: Scotia Gas Networks plc, Socrate spa, and National Grid, each at 10% in the Energy segment.

There were no supplier concentrations greater than 10% during the three months ended March 31, 2017. During the three months ended March 31, 2016, CUI had one supplier concentration of 10%, related to inventory product received.

The Company had revenue concentration in the United Kingdom for the three months ended March 31, 2017 and 2016 of 17% and 22%, respectively.

At March 31, 2017 and December 31, 2016, the Company had trade accounts receivable concentrations in the United Kingdom of 28% and 27%, respectively.