Haw. Rev. Stat. § 237-9.5: No separate licensing, filing, or liability for certain revocable trusts.

In the case of any trust that, for state and federal income tax reporting purposes:

(1) Has no registration or filing requirements separate and apart from its grantor or grantors;

(2) Is subject to the requirement that all items of income, deduction, and credit are to be reported by the individual grantor or grantors; and

(3) Is revocable by the grantor or grantors;

no licensing, registration, or filing requirements under this chapter shall apply; provided that the individual grantor or grantors must be licensed under this chapter and pay the appropriate general excise tax on trust income, if the trust income is from engaging in business.