What is Subcontractor IR35?

IR35 (also known as the off-payroll working rules) determines whether a subcontractor providing services through their own limited company is treated as employed or self-employed for tax purposes. Since April 2021, medium and large private-sector clients are responsible for making the status determination. Inside-IR35 engagements attract PAYE and NIC deductions at source. Sole traders are outside IR35 but may still face employment-status tests.