Box 12 with a code c is the taxable cost of group-term insurance over $50,000. If you had group term life insurance through your workplace, the
premiums for any value over $50,000 become taxable income to you and are
included in box 12.
Enter your W-2 form with the box 12 code C in your tax return. The taxable amount is already included in your Box 1 wages. You don't enter the amount anywhere else in your return.
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