What relevant assertion do auditors primarily focus on when auditing asset balances?

When auditors focus on asset balances during an audit, the primary relevant assertion they concentrate on is existence. This assertion is crucial because it ensures that the assets reported on the financial statements actually exist at the date of the financial statements. Auditors must verify that all listed assets are not only recorded but can be substantiated through direct observation or verification of ownership and rights.

For example, when auditing cash balances, an auditor may perform bank confirmations to validate that the amounts reported are indeed held in the bank at the stated date. Similarly, with inventory, an auditor may conduct physical counts to ascertain that the quantities stated in the financial records align with what is physically present.

While completeness, allocation, and rights and obligations are also important assertions, they serve different purposes. Completeness ensures that all assets are recorded and not omitted, which is more about the comprehensiveness of the financial statements as opposed to verifying the existence of reported assets. Allocation pertains to the proper accounting and valuation of those assets, while rights and obligations deal with ensuring that the reporting entity has the rights to those assets and is legally obliged for the related liabilities. Existence is central as it addresses the fundamental question of whether the assets presented in the financial statements are indeed real and not fictitious.