Business Concentration and Credit Risks

Credit Risks

Financial instruments, mainly within the electrical construction operations, which potentially subject the Company to concentrations of credit risk, consist principally of accounts receivable and accrued billings in the amounts of $21.6 million and $19.1 million as of December 31, 2017 and 2016, respectively, which management reviews to assess the need to establish an allowance for doubtful accounts.

Cash and Cash Equivalents

The Company holds cash on deposit in U.S. banks, in excess of Federal Deposit Insurance Corporation insurance limits. The Company has not experienced and does not anticipate any losses in any such accounts. The Company mitigates this risk by doing business with well capitalized, quality financial institutions.

Customer Concentration

Revenue (in thousands of dollars) to customers exceeding 10% of the Company’s total revenue for the years ended December 31 as indicated are as follows:



	2017			2016
	Amount		% of Total revenue	Amount		% of Total revenue
Electrical construction operations
Customer A	$	38,306	34	$	23,669	18
Customer B	—		—	18,630		14
Customer C	16,912		15	33,770		26
Customer D	11,681		10	—		—

Revenue by service/product (in thousands of dollars) for the years ended December 31 as indicated are as follows:



	2017			2016
	Amount		% of Total revenue	Amount		% of Total revenue
Electrical construction operations
Principal electrical construction operations ⁽¹⁾	$	100,305	88	$	118,748	91
Other electrical construction ⁽²⁾	8,850		8	7,023		5
Total	109,154		96	125,771		96
All other	4,799		4	4,652		4
Total revenue	$	113,954	100	$	130,423	100

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⁽¹⁾ Principal electrical construction operations includes revenue from transmission lines, distribution systems, substations and drilled pier foundations. ⁽²⁾Other electrical construction includes revenue from storm work, fiber optics and other miscellaneous electrical construction items.

The total of the above categories may differ from the sum of the components due to rounding.