Which of the following is excluded from operating expenses (Opex)?

Financing costs are excluded from operating expenses (Opex) because these costs pertain to the method of capital acquisition and not the day-to-day operations of the property itself. Operating expenses are more closely related to the ongoing costs needed to manage and maintain a property, such as maintenance, utilities, and staff salaries, which directly support the property's ability to generate income.

Financing costs, which might include interest payments on loans or costs associated with securing funding, are classified separately in financial statements under financing expenses. This distinction is important for property owners and investors to understand, as Opex significantly impacts the net operating income (NOI) when evaluating a property's financial performance.

In contrast, variable costs, fixed costs, and maintenance costs are all integral to the everyday functionality and upkeep of the property, thus included in the operating expenses category. This clear demarcation helps in accurately assessing the operational efficiency of the property without the influence of financing strategies.