Company prepare budget and use budget as a performance benchmark and monitoring tools. For instance, senior management can question sales department if their actual yeat-to-date entertainment has exceeded the budget before the end of the year. Budget is , usually, prepared and approved at the beginning of the year or before that.
Budget has incorporated management's forecast, estimation and outlook of the business in the coming times.
Is management's budget useful to auditor?
The answer is yes. Budget, which represents management's expectation, should be compared against the actual results. Significant variances should be investigated. Apparently, management would have to explain the variances. It's important for auditor to find out the reason of the variances to identify potential changes in business operation, significant developments during the year.
Understanding how management view the business (by looking at the budget) is a crucial stage in audit planning, it enhance our knowledge and understanding on the business, the industry and the overall economy as a whole.