A tax liability is based on a tax rate, which may be either flat rate or an increasing-rate schedule. In the latter case, tax rates are kept low for moderate-income taxpayers, and then increase for higher-income taxpayers. The tax rate may also vary depending on the nature of the related income. For example, the tax rate on capital gains differs from the rate on operating income.
An organization should pay its tax liabilities when due, for the applicable government authorities usually have the right to collect unpaid taxes, and so can place a lien on an entity's assets.