The Company generates sales in the United States; however, several of its products are sold into various foreign countries, which subjects the Company to the risks of doing business abroad. In addition, the Company operates in the footwear industry, and its business depends on the general economic environment and levels of consumer spending. Changes in the marketplace may significantly affect management’s estimates and the Company’s performance. Management performs regular evaluations concerning the ability of customers to satisfy their obligations and provides for estimated doubtful accounts. Domestic accounts receivable, which generally do not require collateral from customers, were $317.8 million and $206.1 million before allowances for bad debts, sales returns and chargebacks at March 31, 2018 and December 31, 2017, respectively. Foreign accounts receivable, which in some cases are collateralized by letters of credit, were $394.6 million and $251.0 million before allowance for bad debts, sales returns and chargebacks at March 31, 2018 and December 31, 2017, respectively. The Company’s credit losses attributable to write-offs for the three months ended March 31, 2018 and 2017 were $2.0 million and $0.1 million, respectively.

Assets located outside the U.S. consist primarily of cash, accounts receivable, inventory, property, plant and equipment, and other assets. Net assets held outside the United States were $1.364 billion and $1.273 billion at March 31, 2018 and December 31, 2017, respectively.

The Company’s net sales to its five largest customers accounted for approximately 10.8% and 13.2% of total net sales for the three months ended March 31, 2018 and 2017, respectively. No customer accounted for more than 10.0% of the Company’s net sales during the three months ended March 31, 2018 and 2017. No customer accounted for more than 10.0% of trade receivables at March 31, 2018 or December 31, 2017.

The Company’s top five manufacturers produced the following, as a percentage of total production, for the three months ended March 31, 2018 and 2017:

The majority of the Company’s products are produced in China and Vietnam. The Company’s operations are subject to the customary risks of doing business abroad, including, but not limited to, currency fluctuations and revaluations, custom duties and related fees, various import controls and other monetary barriers, restrictions on the transfer of funds, labor unrest and strikes, and, in certain parts of the world, political instability. The Company believes it has acted to reduce these risks by diversifying manufacturing among various factories. To date, these business risks have not had a material adverse impact on the Company’s operations.