Article 15 of the KSA Income Tax Law establishes the general principle regarding the tax treatment of reserves and allocations. It states that no reserves or allocations are permitted as deductible expenses against taxable income. This rule applies broadly to all taxpayers. However, the Article provides a specific and singular exception for banks, which are allowed to deduct allocations made specifically for doubtful debts. It further stipulates that the precise rules, limitations, and conditions for determining the allowable doubtful debt allocations for banks are to be defined by the implementing Regulations, thereby delegating the technical specifics to supplementary legislation.