diff --git a/src/lib/LibTokenOwnership.sol b/src/lib/LibTokenOwnership.sol
new file mode 100644
index 00000000..2ac8eae7
--- /dev/null
+++ b/src/lib/LibTokenOwnership.sol
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: LicenseRef-DCL-1.0
+// SPDX-FileCopyrightText: Copyright (c) 2020 Rain Open Source Software Ltd
+pragma solidity ^0.8.25;
+
+/// @notice Minimal `Ownable`-like surface used by ST0x receipt vaults.
+/// Every production receipt vault exposes `owner()`; this library only
+/// needs the getter, not the transfer/renounce mutators.
+interface IOwnable {
+    /// @notice The current owner of the contract.
+    /// @return The owner address.
+    function owner() external view returns (address);
+}
+
+/// @notice A receipt vault's `owner()` does not match the caller-supplied
+/// expected owner. Used by `assertUniformOwnership` to surface the exact
+/// vault address that breaks the invariant rather than a generic mismatch.
+/// @param vault The receipt vault whose owner was read.
+/// @param expected The caller-supplied expected owner.
+/// @param actual The owner address returned by `vault.owner()`.
+error ReceiptVaultOwnerMismatch(address vault, address expected, address actual);
+
+/// @title LibTokenOwnership
+/// @notice Pinned addresses for the ST0x production receipt vaults on Base
+/// and helpers for asserting that every vault shares the same `owner()`.
+/// Consumed by the multisig threshold migration tooling to confirm that the
+/// Safe whose threshold is being changed actually controls every production
+/// vault before the migration runs, and that no vault has drifted out of
+/// the shared ownership set.
+/// @dev Addresses are sourced from `st0x.registry/token-lists/base.json`
+/// (`extensions.unwrappedAddress` per token entry). Only the 13 current
+/// production receipt vaults participate in the invariant — deprecated
+/// (legacy) receipt vaults are intentionally excluded because they are not
+/// part of ongoing operations and bundling them into an operational
+/// invariant would tie live drift detection to assets that are no longer
+/// actively managed.
+library LibTokenOwnership {
+    /// @notice NVIDIA wtNVDA receipt vault — current.
+    address internal constant ST0X_RECEIPT_VAULT_NVDA = 0x7271A3C91Bb6070eD09333B84a815949D4f16d14;
+
+    /// @notice Amazon wtAMZN receipt vault — current.
+    address internal constant ST0X_RECEIPT_VAULT_AMZN = 0x466CB2e46Fa1AfC0AB5e22274B34d0391db18eFd;
+
+    /// @notice Tesla wtTSLA receipt vault — current.
+    address internal constant ST0X_RECEIPT_VAULT_TSLA = 0x4E169cD2Ab4f82640a8c65C68feD55863866fDB0;
+
+    /// @notice MicroStrategy wtMSTR receipt vault — current.
+    address internal constant ST0X_RECEIPT_VAULT_MSTR = 0x013b782F402d61aa1004CCA95b9f5Bb402c9d5FE;
+
+    /// @notice iShares Gold Trust wtIAU receipt vault — current.
+    address internal constant ST0X_RECEIPT_VAULT_IAU = 0x9A507314EA2a6C5686C0D07BfecB764dCF324dFF;
+
+    /// @notice Coinbase wtCOIN receipt vault — current.
+    address internal constant ST0X_RECEIPT_VAULT_COIN = 0x626757e6F50675D17fcAd312E82f989aE7A23d38;
+
+    /// @notice SPDR Portfolio S&P 500 wtSPYM receipt vault — current.
+    address internal constant ST0X_RECEIPT_VAULT_SPYM = 0x8Fdf41116F755771Bfe0747D5F8C3711D5DEbfBb;
+
+    /// @notice abrdn Physical Silver wtSIVR receipt vault — current.
+    address internal constant ST0X_RECEIPT_VAULT_SIVR = 0x58cE5024B89B4f73C27814C0f0aBbEa331C99Be8;
+
+    /// @notice Circle wtCRCL receipt vault — current.
+    address internal constant ST0X_RECEIPT_VAULT_CRCL = 0x38Eb797892ED71Da69bDc27A456A7c83Ff813b52;
+
+    /// @notice Bitmine Immersion wtBMNR receipt vault — current.
+    address internal constant ST0X_RECEIPT_VAULT_BMNR = 0xfBde45dF60249203b12148452fC77C3B5F811eB2;
+
+    /// @notice abrdn Physical Platinum wtPPLT receipt vault — current.
+    address internal constant ST0X_RECEIPT_VAULT_PPLT = 0x1f17523b147CcC2A2328c0F014f6d49c479ea063;
+
+    /// @notice iShares iBonds 2027 HY wtIBHG receipt vault — current.
+    address internal constant ST0X_RECEIPT_VAULT_IBHG = 0x3c0F093aa1eD511910279b2C8d56eF5c96f1a6cF;
+
+    /// @notice iShares 0-3 Month Treasury wtSGOV receipt vault — current.
+    address internal constant ST0X_RECEIPT_VAULT_SGOV = 0xc941C1506B7555Ba8C506Fb6c9b9CC259902d612;
+
+    /// @notice The 13 production receipt vaults backing the current
+    /// `wt<TICKER>` wrappers, in registry order (NVDA, AMZN, TSLA, MSTR,
+    /// IAU, COIN, SPYM, SIVR, CRCL, BMNR, PPLT, IBHG, SGOV). Order is
+    /// fixed so callers can index into it against the registry without
+    /// re-sorting.
+    /// @return The current-production receipt vault addresses.
+    function productionReceiptVaults() internal pure returns (address[] memory) {
+        address[] memory vaults = new address[](13);
+        vaults[0] = ST0X_RECEIPT_VAULT_NVDA;
+        vaults[1] = ST0X_RECEIPT_VAULT_AMZN;
+        vaults[2] = ST0X_RECEIPT_VAULT_TSLA;
+        vaults[3] = ST0X_RECEIPT_VAULT_MSTR;
+        vaults[4] = ST0X_RECEIPT_VAULT_IAU;
+        vaults[5] = ST0X_RECEIPT_VAULT_COIN;
+        vaults[6] = ST0X_RECEIPT_VAULT_SPYM;
+        vaults[7] = ST0X_RECEIPT_VAULT_SIVR;
+        vaults[8] = ST0X_RECEIPT_VAULT_CRCL;
+        vaults[9] = ST0X_RECEIPT_VAULT_BMNR;
+        vaults[10] = ST0X_RECEIPT_VAULT_PPLT;
+        vaults[11] = ST0X_RECEIPT_VAULT_IBHG;
+        vaults[12] = ST0X_RECEIPT_VAULT_SGOV;
+        return vaults;
+    }
+
+    /// @notice Assert that every receipt vault returned by
+    /// `productionReceiptVaults()` has its `owner()` set to `expectedOwner`.
+    /// Reverts with `ReceiptVaultOwnerMismatch` on first mismatch,
+    /// surfacing the offending vault and both owners so the calling
+    /// pre-flight pinpoints the drift.
+    /// @param expectedOwner The owner every production receipt vault is
+    /// expected to report.
+    function assertUniformOwnership(address expectedOwner) internal view {
+        address[] memory vaults = productionReceiptVaults();
+        for (uint256 i = 0; i < vaults.length; i++) {
+            address actualOwner = IOwnable(vaults[i]).owner();
+            if (actualOwner != expectedOwner) {
+                revert ReceiptVaultOwnerMismatch(vaults[i], expectedOwner, actualOwner);
+            }
+        }
+    }
+}
diff --git a/test/src/lib/LibTokenOwnership.t.sol b/test/src/lib/LibTokenOwnership.t.sol
new file mode 100644
index 00000000..50bc030b
--- /dev/null
+++ b/test/src/lib/LibTokenOwnership.t.sol
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: LicenseRef-DCL-1.0
+// SPDX-FileCopyrightText: Copyright (c) 2020 Rain Open Source Software Ltd
+pragma solidity =0.8.25;
+
+import {Test} from "forge-std-1.16.1/src/Test.sol";
+import {LibTokenOwnership, IOwnable, ReceiptVaultOwnerMismatch} from "../../../src/lib/LibTokenOwnership.sol";
+import {LibProdSafes} from "../../../src/lib/LibProdSafes.sol";
+import {LibRainDeploy} from "rain-deploy-0.1.2/src/lib/LibRainDeploy.sol";
+
+/// @title LibTokenOwnershipHarness
+/// @notice External-call harness so `vm.expectRevert` can intercept the
+/// typed `ReceiptVaultOwnerMismatch` revert. `expectRevert` only catches
+/// reverts originating at a lower call depth than the cheatcode itself;
+/// library `internal` calls inline.
+contract LibTokenOwnershipHarness {
+    function callAssertUniformOwnership(address expected) external view {
+        LibTokenOwnership.assertUniformOwnership(expected);
+    }
+}
+
+/// @title LibTokenOwnershipTest
+/// @notice Live fork tests pinning every ST0x receipt vault to the same
+/// `owner()` (the ST0x token-owner Safe), plus an inverted test that
+/// injects drift via `vm.mockCall` on a single vault and asserts the
+/// typed `ReceiptVaultOwnerMismatch` revert surfaces it. Uses an unpinned
+/// head fork to keep the assertion live; see precedent in
+/// `LibProdSafes.t.sol::selectBaseFork`.
+contract LibTokenOwnershipTest is Test {
+    /// @notice External-call harness allocated per test against the
+    /// active fork. Recreated by `selectBaseFork` because
+    /// `vm.createSelectFork` resets cheatcode state.
+    LibTokenOwnershipHarness internal harness;
+
+    /// @notice Selects the Base fork at chain head — deliberately
+    /// unpinned. The vault `owner()` set should track live state so the
+    /// next CI run flags any drift.
+    function selectBaseFork() internal {
+        vm.createSelectFork(LibRainDeploy.BASE);
+        harness = new LibTokenOwnershipHarness();
+    }
+
+    /// @notice Live positive test: every receipt vault returned by
+    /// `productionReceiptVaults()` has `owner() == STOX_TOKEN_OWNER_SAFE`.
+    function testAssertUniformOwnershipLive() external {
+        selectBaseFork();
+        LibTokenOwnership.assertUniformOwnership(LibProdSafes.STOX_TOKEN_OWNER_SAFE);
+    }
+
+    /// @notice `productionReceiptVaults()` returns 13 entries — the
+    /// current registry set. Drift here would mean the registry got a new
+    /// (or lost an) entry without the constants being updated.
+    function testProductionReceiptVaultsCount() external pure {
+        address[] memory vaults = LibTokenOwnership.productionReceiptVaults();
+        assertEq(vaults.length, 13, "expected 13 production vaults");
+    }
+
+    /// @notice Inverted test: mock the NVDA vault's `owner()` to a rogue
+    /// address and assert `assertUniformOwnership` reverts with
+    /// `ReceiptVaultOwnerMismatch` pinpointing that vault.
+    function testInvertedOwnershipMismatchOnSingleVault() external {
+        selectBaseFork();
+        address rogueOwner = address(0xBADC0DE);
+        address victimVault = LibTokenOwnership.ST0X_RECEIPT_VAULT_NVDA;
+        vm.mockCall(victimVault, abi.encodeWithSelector(IOwnable.owner.selector), abi.encode(rogueOwner));
+
+        vm.expectRevert(
+            abi.encodeWithSelector(
+                ReceiptVaultOwnerMismatch.selector, victimVault, LibProdSafes.STOX_TOKEN_OWNER_SAFE, rogueOwner
+            )
+        );
+        harness.callAssertUniformOwnership(LibProdSafes.STOX_TOKEN_OWNER_SAFE);
+    }
+}