OPEX, or Operating Expenses, is a term used to refer to the ongoing costs of running a business. This includes expenses such as salaries, utilities, supplies, and other costs that are incurred on a regular basis in the course of operating a business. OPEX is in contrast to capital expenditure (CAPEX), which is the money that a company spends on acquiring or upgrading physical assets, such as property, buildings, or equipment. OPEX is typically an ongoing cost, while CAPEX is a one-time expense. The distinction between the two is important because they are often treated differently for financial reporting and tax purposes.