Exemption denial for trusts: specified uses, non-arm's-length transactions and related party benefits remove tax exemption. Section 13 lists specific circumstances in which the exemptions under section 11 (and section 12) are disallowed: trusts for private religious purposes or those created for particular religious communities; situations where income or property enures to or is applied for the benefit of specified persons; non-arm's-length transactions, inadequate consideration for loans, services or leases, diversion of income, and investments in concerns where specified persons have substantial interest. The section defines specified persons, sets tests for substantial interest, and provides exceptions, transitional rules, and computation rules where exemption is denied.