There is no easy answer as every circumstance is different and laws vary from state to state. Here are some general guidelines:
Short term disability (STD) payments can take one of two forms. They can be a taxable wage replacement benefit, or a non-taxable insurance benefit.
Whether a STD benefit is taxable or not depends on who is paying the premium to the insurance company.
If your employer pays the premium for the disability insurance product, than any payment you receive is taxable to you as a taxable wage replacement payment. The insurance contract is considered to be a "wage replacement" and not a pure insurance payment.
If you, the employee, purchase the insurance product with after tax money, than the payment of the benefit is not taxable income to you. The payments you receive are not considered to be a wage replacement payment.
The taxable benefit is not reported on a Form 1099. The taxable benefit will be reported on your W-2 that is issued by your employer, or reported on a Form W-2 issued by the insurer, depending on the arrangement your employer has with the insurance company providing the benefits.
If it is taxable and reported on a W2 then it would entered in the "Wages and Income" category in the "Wages and Salaries" section.
