Return filing requirement for business trusts expanded, treating them as annual taxpayers subject to standard income-tax provisions. Clauses inserted into subsection (4C) include mutual funds, securitisation trusts, and venture capital companies or funds among the enumerated categories, with cross-reference wording amended accordingly. A new subsection (4E) mandates that every business trust not otherwise required to furnish a return must file an annual return of income or loss, and all provisions of the Income-tax Act shall apply to such returns as if furnished under the principal return-filing provision.