What is the significance of a valid Social Security number for tax returns?

A valid Social Security number (SSN) is crucial for tax returns because it uniquely identifies taxpayers within the IRS system. Every individual who files a tax return must include their SSN to establish their identity, track earnings, and determine their eligibility for various tax credits and deductions. By requiring an SSN, the IRS can ensure accurate reporting and help prevent identity theft and fraud within the tax system.

This requirement applies to all individuals submitting tax returns, including dependents. It is necessary not only for tracking purposes but also for the calculation of benefits such as Social Security, which are tied to reported earnings and tax contributions documented through the SSN. Without a valid SSN, a taxpayer's return may be rejected, and they could face challenges in receiving any potential refund or credits for which they would be eligible.