Accumulation of charitable income: Form No.10 filing and investment obligations determine tax treatment under section 11. Notice obligations require trustees to file Form No.10 stating a resolution to accumulate or set apart a specified amount or percentage of income, the purposes and period of accumulation, and that the sums have been invested or deposited in permitted forms under sub section (5) of section 11. The statement must disclose prior accumulations, amounts applied or remaining, any amounts deemed to be income, and income which could not be applied due to court orders; it must be signed by a trustee or principal officer and accompanied by accounts and investment details within prescribed timeframes.