The background rule this is an exception to. A spendthrift provision stops a beneficiary's creditors from reaching the beneficiary's interest before it is paid out. It has never done anything for the person who created the trust: under the ordinary rule, a settlor's creditor can reach the maximum amount the trustee could distribute for the settlor's own benefit, whether or not the trust contains a spendthrift clause. That is the rule the statutes behind these trusts set aside, and it is why the arrangement is described as "self-settled": the settlor and a beneficiary are the same person.
What a state statute actually asks for. Wyoming Statute 4-10-510 requires a trust instrument that says it is a qualified spendthrift trust under that section, expressly adopts Wyoming law, contains a spendthrift provision described as "a restriction on the transfer of the settlor's beneficial interest ... enforceable under applicable nonbankruptcy law within the meaning of Section 541(c)(2) of the Bankruptcy Code," and is irrevocable. That last requirement is looser than it sounds. The same section lists powers the settlor may keep without the trust being treated as revocable, including a veto over distributions, a power of appointment, the receipt of income, the receipt each year of a stated percentage of the trust's value not exceeding five percent, discretionary distributions of principal made by a qualified trustee, and the right to remove and replace the trustee or a trust protector.
Wyoming Statute 4-10-517 then narrows what a creditor can do: a creditor of the settlor "has only those rights ... as are provided in W.S. 4-10-514 through 4-10-523," and must prove "by clear and convincing evidence that the transfer of property to the trust was a fraudulent transfer" under the Uniform Fraudulent Transfers Act. The section adds a detail worth noticing: proof by one creditor that a transfer was fraudulent "does not constitute proof as to any other creditor," so each claimant starts over.
Nevada shows the other half of the design, which is timing. Nevada Revised Statute 166.170 gives a person who was already a creditor when the transfer was made two years from the transfer, or six months from discovering it, whichever is later. Someone who becomes a creditor afterward has two years from the transfer and nothing more. Subsection 2 treats a public record of the transfer as discovery, and subsection 3 requires clear and convincing evidence either that the transfer was fraudulent under Nevada's fraudulent-transfer chapter or that it violated a legal obligation the settlor owed the creditor under a contract or an enforceable court order.
Nevada attaches two structural conditions as well. Under NRS 166.040(1)(b), a spendthrift trust may be created for the settlor's own benefit only where the writing "is irrevocable, does not require that any part of the income or principal of the trust be distributed to the settlor, and was not intended to hinder, delay or defraud known creditors." And under NRS 166.015, if the settlor is a beneficiary, at least one trustee must be a natural person resident and domiciled in Nevada, a trust company maintaining a Nevada office, or a bank with a Nevada office that possesses and exercises trust powers. A trust of this kind is therefore not a document that can be signed and forgotten; it requires a trustee in the state, indefinitely.
The federal overlay, and the sentence that is usually mis-stated. Section 548(e)(1) of the Bankruptcy Code lets a bankruptcy trustee avoid a transfer made within ten years before the petition, which is far longer than any state deadline. It is routinely described as a flat ten-year clawback on these trusts. It is not. The provision requires all four of its elements: the transfer was to "a self-settled trust or similar device", it was made by the debtor, the debtor is a beneficiary of the trust, and the debtor made it "with actual intent to hinder, delay, or defraud" a creditor. Element (D) is where the contest happens. Subsection (e)(2) then widens what counts as a transfer for this purpose, so that it "includes a transfer made in anticipation of any money judgment, settlement, civil penalty, equitable order, or criminal fine" the debtor incurred or believed would be incurred from a securities-law violation, or from fraud, deceit or manipulation in a fiduciary capacity or in connection with the purchase or sale of a registered security.
The unresolved question the marketing rarely raises. These statutes are state law, and the person a creditor is suing usually lives somewhere else. A court in the settlor's home state, applying its own public policy to a resident's transfer of local property, may not defer to another state's statute. That conflict is real, it is litigated, and it means the protection a domestic trust actually delivers depends on where the eventual lawsuit is brought, not only on how the document was drafted.
Offshore trusts change the enforcement question rather than the legal one. The appeal of a foreign trustee is jurisdictional: a US court has no power to order a trustee it cannot reach. But it does have power over the settlor, who is normally still in the United States, and the natural response to an unproduced asset is an order directed at that person. Two further costs are certain rather than contingent. The arrangement is expensive to establish and maintain, and a US owner of a foreign trust carries annual reporting obligations, on Form 3520, "Annual Return To Report Transactions With Foreign Trusts and Receipt of Certain Foreign Gifts," and on Form 3520-A, "Annual Information Return of Foreign Trust With a U.S. Owner." Neither form reduces any tax; both carry penalties for being late.