Start with the number, because it's the kind of figure that should be a lot more widely known than it is. South Dakota's own Division of Banking reports trust assets held in the state grew from $590 billion at the end of 2022, to $680 billion at the end of 2023, to $815 billion at the end of 2024 -- and reporting in 2026 puts the figure above $900 billion.^[1] That's larger than the GDP of Switzerland. It's sitting in a state with fewer than a million residents, in an industry most Americans have never had a reason to look into.

The mechanism isn't secrecy alone -- it's a specific legal feature almost no other US state offers. Most states' trust laws impose a "rule against perpetuities" -- a legal limit on how long a trust can exist before its assets have to be distributed, historically capped at roughly 21 years past the life of someone alive when the trust was created. South Dakota abolished that rule for trusts formed there, meaning a South Dakota trust can legally run forever -- true, unlimited perpetuity, passing wealth down through a family indefinitely without ever triggering the estate and gift taxes a new transfer would normally incur.^[2] Competing jurisdictions cap it: Nevada allows 365 years, Delaware caps trusts holding real property at 100 years.^[2] South Dakota's law is more permissive than either.

Privacy is the second, compounding piece of the same design. South Dakota trusts benefit from automatic sealing provisions that go further than Delaware's or Nevada's own privacy protections -- court records related to a South Dakota trust can be sealed by default, without the trust's beneficiaries needing to petition a court and argue for it case by case.^[2] Combined with true perpetuity, the result is a jurisdiction built specifically to hold and grow a family's wealth across generations, largely invisible to anyone outside the family and its trustees.

Part of the recent growth is a genuinely new-economy story layered onto an old-economy legal structure. A meaningful share of the jump from $680 billion to $815 billion-plus between 2023 and 2024 is attributed directly to cryptocurrency asset appreciation held inside these trust structures^[1] -- a 19th-century-style dynasty-trust legal framework, built in the 1980s specifically to compete for this kind of capital, now holding 21st-century digital assets whose value swung sharply upward in the same window. The legal tool built for old family fortunes turned out to work just as well for new ones.

None of this is illegal, and treating it as a scandal would misread what it actually is. Every piece of this is lawful estate planning, using state-level legal competition the same way South Dakota's credit-card deal with Citibank used it forty years earlier -- one state offering a legal environment no other state matches, and wealth moving to wherever that environment exists. The pattern is the same mechanism as the Citibank story, aimed at a different kind of asset: a small state, with little else to compete on nationally, builds one specific legal advantage nobody else offers, and the entire country's capital responds to the incentive it created, mostly without noticing where it actually went.