You need the total value of a business. Examples include estimating the post aquisition value (tax and/or financial reporting) of a business, the sale of a business to a family member, or the transfer of a business under a buy-sell agreement.

You need the equity value (or an equity class value) of a business. Examples include the transfer of a business interest by gift, the issuance of equity compensation awards, financial reporting for warrants or other equity based instruments.

You need to value something related to a business but not the business itself. Examples include financial reporting for convertible debt, market-based equity compensation awards, or derivatives.