The 'IR35' rules are designed to prevent the avoidance of tax and national insurance contributions (NIC) through the use of personal service companies and partnerships. The rules do not stop individuals selling their services through either their own personal companies or a partnership. However, they do seek to remove any possible tax advantages from doing so. Intermediaries who have operated the IR35 concession to delay making a final return and payment for the tax year ending 5 April 2015, have until 31 January 2016 to submit accurate figures and pay any outstanding amounts of PAYE and NIC due. The concession operates where a provisional return and payment have been submitted but cannot be confirmed because final figures of income, including the calculation of the 'deemed payment', were not known at the end 2015 tax year. HMRC advise that adjustments to the provisional RTI return should be reported using 'an Earlier Year Update (EYU)' and must be submitted electronically to HMRC by 31 January 2016. Interest will be charged on any balancing payment. Please advise us if you would like help with this issue. Internet links: GOV.UK IR35 guidance Employer Bulletin