Most likely because a casualty loss that low will almost always have no impact on your tax return. Casualty losses are handled by first deducting $100, then applying a 10% of AGI threshold. So, in your case, your AGI would have to be below $4500 ($550 - $100) * 10 for you to get an itemized deduction from the loss. In addition, the total of all your itemized deductions would have to be greater than the standard deduction for your filing status to have an impact.