Start-up tax deduction enables eligible start-ups to claim full exemption on profits for a limited consecutive period within initial years. A new provision allows a deduction equal to one hundred per cent of profits and gains derived by an eligible start-up from an eligible business for three consecutive assessment years, claimable at the option of the assessee for any three consecutive years within five years from incorporation. The provision applies only to businesses involving technology or IP-driven innovation, to start-ups incorporated within the prescribed window with turnover below the specified threshold, and to those holding a certificate from the Inter-Ministerial Board of Certification, while excluding entities formed by splitting up or by transfer of previously used domestic machinery except as explained.