The accounting concept that states that a firm's financial affairs must be separated from that of the owner's private transactions is

The accounting concept that states that a firm's financial affairs must be separated from that of the owner's private transactions is the "business entity" concept. This concept recognizes that the business is a separate entity from its owners and requires the financial transactions of the business to be recorded separately from the personal transactions of the owners. This means that the business must have its own set of accounts, which are separate from the personal accounts of the owners. The concept is important in ensuring that the financial statements of the business reflect its true financial position and performance, without being affected by the personal transactions of the owners.