The tax burden of value-added tax is generally understood as the ratio of taxable amount to sales income. And profit is the balance of operating income MINUS operating costs. In principle, when the purchase cost is fixed (that is, the input tax is basically unchanged), the higher the sales income (the higher the selling price), the greater the output tax and the greater the profit rate. In other words, the greater the VAT burden of the same product (vertical comparison, not horizontal comparison with other enterprises), the higher the profit rate. This is also why the tax bureau often checks the operating costs and accounts payable of some enterprises when it sees great changes in their VAT tax burden, so as to prevent enterprises from recovering VAT invoices issued on their behalf (evading input tax and inflating costs at the same time)-it is abnormal for enterprises that have failed for a long time.