Is my sick pay taxable?

Withholding

An amount taken from income as a prepayment of an individual’s tax liability for the year. In the case of wages, the employer withholds part of every wage payment. Backup withholding from dividend or interest income is required if you do not provide the payer with a correct taxpayer identification number. Withholding on pensions and IRAs is automatic unless you elect to waive withholding.