Net operating working capital captures multiple dimensions of firms’ adjustments to operating and financial conditions. Sales growth, uncertainty of sales, costly external financing, and financial distress encourage firms to pursue more aggressive working capital strategies. Firms with greater internal financing capacity and superior capital market access employ more conservative working capital policies. Results are robust to unobserved heterogeneity and industry effects. The evidence suggests that operating and financing conditions should be considered when evaluating working capital behavior, not just industry averages. Additionally, industry concentration magnifies the effect of sales growth.