Which of the following is included in net operating income calculations?

Net operating income (NOI) is a key financial metric used in real estate to assess the profitability of an income-generating property. It represents the total revenue from the property minus the operating expenses.

Operating expenses, which are essential for calculations of NOI, include costs such as maintenance, property management, insurance, utilities, and property taxes—all necessary for the operation of the property but excluding any financing costs or income tax liabilities. By focusing specifically on the operational aspect—hence the term "operating income"—this measure allows investors to understand the cash flow available from a property before considering how that income will be affected by loans or tax obligations.

In the context of the options provided, only the deduction of operating expenses from gross income accurately reflects how net operating income is calculated. Other potential factors, like tax liabilities or sales income, do not apply directly to the operating income from the property. Thus, recognizing that net operating income is specifically derived from the operating expenses subtracted from gross income clarifies the emphasis on ongoing operational costs.