S. 263 : Commissioner-Revision of orders prejudicial to revenue-Fund investors resident of various countries-Non-fulfilment of condition of Liable to tax-Tax Exemption by resident country does not give right to Revenue Authorities to tax income in contracting State —Derivatives-Contention of Principal Commissioner that income earned from derivatives not business income is not accepted-Revision order is quashed. [S. 2(29A),6, 10(23FE, 900, 90A]