Registration of sub-accounts: eligibility, FII sponsorship, undertakings and fees govern access to FII tax benefits. The Board grants registration to sub-accounts upon assessing categorical eligibility (specified fund, corporate, individual or charitable categories), fit-and-proper status, sponsorship by a registered and authorised FII, submission of prescribed joint undertakings, and payment of registration fees; registered sub-accounts are deemed registered as FIIs for limited income-tax benefit purposes.