What Is Working Capital and How to Calculate It from SEC Filings

The Working Capital Formula

Working capital is current assets minus current liabilities. It represents the liquid buffer a company maintains to fund day-to-day operations and meet obligations coming due within the next twelve months. A positive working capital balance means current assets exceed current liabilities — the company can cover its near-term obligations from assets it expects to convert to cash within a year. Negative working capital means the opposite.

Components of Working Capital

Current assets typically include: cash and cash equivalents, short-term investments, accounts receivable (money owed by customers), inventory (goods held for sale), and prepaid expenses. Current liabilities include: accounts payable (money owed to suppliers), accrued expenses, short-term debt, and the current portion of long-term debt.

Changes in Working Capital Matter as Much as the Level

Working capital trends are often more informative than the absolute level. A company whose accounts receivable are growing much faster than revenue may be extending credit to customers who are struggling to pay — a potential precursor to write-offs. Inventory building faster than sales can signal slowing demand. These dynamics appear in the cash flow statement as "changes in operating assets and liabilities" — a section many investors overlook but which often contains early warning signals.

Negative Working Capital Isn't Always Bad

Some highly efficient businesses — retailers, subscription companies, fast food franchises — naturally operate with negative working capital because customers pay before the company pays its suppliers. Amazon is the canonical example. In these business models, negative working capital is a sign of supplier leverage and cash flow efficiency, not financial distress.