Conn. Gen. Stat. § 45a-542p: Insubstantial allocations not required.

If a trustee determines that an allocation between principal and income required by section 45a-542q, 45a-542r, 45a-542s, 45a-542t or 45a-542w is insubstantial, the trustee may allocate the entire amount to principal unless one of the circumstances described in subsection (c) of section 45a-542c applies to the allocation. This power may be exercised by a cotrustee in the circumstances described in subsection (d) of section 45a-542c and may be released for the reasons and in the manner described in subsection (e) of said section. An allocation is presumed to be insubstantial if:

(1) The amount of the allocation would increase or decrease net income in an accounting period, as determined before the allocation, by less than ten per cent; or

(2) The value of the asset producing the receipt for which the allocation would be made is less than ten per cent of the total value of the trust's assets at the beginning of the accounting period.