If no specific rule exists for calculating a benefit provided by an employer, the employee is charged on what basis?

When there is no specific rule in place for determining the value of a benefit provided by an employer, the employee is typically charged based on the marginal cost to the employer. This approach focuses on the additional cost incurred by the employer for providing the benefit in question, rather than market value or average costs associated with other employees.

Charging based on marginal cost captures the actual expense the employer experiences in providing the benefit, providing an accurate reflection of the value offered to the employee. This method tends to align the taxation of benefits with economic principles, thus ensuring a fairer assessment of the benefit's worth as it relates to the employer's perspective.

In contrast, market value could fluctuate and may not directly reflect the cost incurred by the employer. Estimated value might not provide a precise basis for taxation compared to the harder data of actual costs. Average cost from all employees may not accurately reflect the specific circumstances of the individual employee receiving the benefit, leading to potential inequities in the way benefits are assessed and taxed. Thus, the marginal cost is the most logical and applicable approach in this context.