diff --git a/packages/inter-protocol/src/auction/auctioneer.js b/packages/inter-protocol/src/auction/auctioneer.js
index 9eb4d101eb4..7a705398dc3 100644
--- a/packages/inter-protocol/src/auction/auctioneer.js
+++ b/packages/inter-protocol/src/auction/auctioneer.js
@@ -98,7 +98,7 @@ const distributeProportionalShares = (
 
   const collShare = makeRatioFromAmounts(unsoldCollateral, totalCollDeposited);
   const currShare = makeRatioFromAmounts(proceeds, totalCollDeposited);
-  /** @type {import('@agoric/zoe/src/contractSupport/atomicTransfer.js').TransferPart[]} */
+  /** @type {TransferPart[]} */
   const transfers = [];
   let proceedsLeft = proceeds;
   let collateralLeft = unsoldCollateral;
@@ -258,7 +258,7 @@ export const distributeProportionalSharesWithLimits = (
   // collateral to reach their share. Then see what's left, and allocate it
   // among the remaining depositors. Escape to distributeProportionalShares if
   // anything doesn't work.
-  /** @type {import('@agoric/zoe/src/contractSupport/atomicTransfer.js').TransferPart[]} */
+  /** @type {TransferPart[]} */
   const transfers = [];
   let proceedsLeft = proceeds;
   let collateralLeft = unsoldCollateral;
diff --git a/packages/inter-protocol/src/vaultFactory/liquidation.js b/packages/inter-protocol/src/vaultFactory/liquidation.js
index f511befd4a1..cf0241696dc 100644
--- a/packages/inter-protocol/src/vaultFactory/liquidation.js
+++ b/packages/inter-protocol/src/vaultFactory/liquidation.js
@@ -280,7 +280,7 @@ export const getLiquidatableVaults = (
   const { zcfSeat: liqSeat } = zcf.makeEmptySeatKit();
   let totalDebt = AmountMath.makeEmpty(debtBrand);
   let totalCollateral = AmountMath.makeEmpty(collateralBrand);
-  /** @type {import('@agoric/zoe/src/contractSupport/atomicTransfer.js').TransferPart[]} */
+  /** @type {TransferPart[]} */
   const transfers = [];
 
   for (const vault of vaultsToLiquidate.values()) {
diff --git a/packages/inter-protocol/src/vaultFactory/types.js b/packages/inter-protocol/src/vaultFactory/types.js
index ecde8bf4f24..c2a6a07c53c 100644
--- a/packages/inter-protocol/src/vaultFactory/types.js
+++ b/packages/inter-protocol/src/vaultFactory/types.js
@@ -70,7 +70,7 @@
  * @param {ZCFSeat} mintReceiver
  * @param {Amount<'nat'>} toMint
  * @param {Amount<'nat'>} fee
- * @param {import('@agoric/zoe/src/contractSupport/atomicTransfer.js').TransferPart[]} transfers
+ * @param {TransferPart[]} transfers
  * @returns {void}
  */
 
diff --git a/packages/inter-protocol/src/vaultFactory/vault.js b/packages/inter-protocol/src/vaultFactory/vault.js
index 9877f4c9f1f..646271ec8ac 100644
--- a/packages/inter-protocol/src/vaultFactory/vault.js
+++ b/packages/inter-protocol/src/vaultFactory/vault.js
@@ -549,7 +549,7 @@ export const prepareVault = (baggage, makeRecorderKit, zcf) => {
 
           const giveMintedTaken = AmountMath.subtract(fp.give.Minted, surplus);
 
-          /** @type {import('@agoric/zoe/src/contractSupport/atomicTransfer.js').TransferPart[]} */
+          /** @type {TransferPart[]} */
           const transfers = harden([
             [clientSeat, vaultSeat, { Collateral: fp.give.Collateral }],
             [vaultSeat, clientSeat, { Collateral: fp.want.Collateral }],
diff --git a/packages/inter-protocol/src/vaultFactory/vaultDirector.js b/packages/inter-protocol/src/vaultFactory/vaultDirector.js
index 47a872c0475..c60b8b2d544 100644
--- a/packages/inter-protocol/src/vaultFactory/vaultDirector.js
+++ b/packages/inter-protocol/src/vaultFactory/vaultDirector.js
@@ -198,7 +198,7 @@ const prepareVaultDirector = (
     mintAndTransfer: (mintReceiver, toMint, fee, nonMintTransfers) => {
       const kept = AmountMath.subtract(toMint, fee);
       debtMint.mintGains(harden({ Minted: toMint }), mintSeat);
-      /** @type {import('@agoric/zoe/src/contractSupport/atomicTransfer.js').TransferPart[]} */
+      /** @type {TransferPart[]} */
       const transfers = [
         ...nonMintTransfers,
         [mintSeat, rewardPoolSeat, { Minted: fee }],
diff --git a/packages/inter-protocol/src/vaultFactory/vaultManager.js b/packages/inter-protocol/src/vaultFactory/vaultManager.js
index 4c84e140bbe..dd9daf9efee 100644
--- a/packages/inter-protocol/src/vaultFactory/vaultManager.js
+++ b/packages/inter-protocol/src/vaultFactory/vaultManager.js
@@ -699,7 +699,7 @@ export const prepareVaultManagerKit = (
           if (plan.transfersToVault.length > 0) {
             const transfers = plan.transfersToVault.map(
               ([vaultIndex, amounts]) =>
-                /** @type {import('@agoric/zoe/src/contractSupport/atomicTransfer.js').TransferPart} */ ([
+                /** @type {TransferPart} */ ([
                   liqSeat,
                   vaultsInPlan[vaultIndex].getVaultSeat(),
                   amounts,
diff --git a/packages/inter-protocol/test/vaultFactory/vault-contract-wrapper.js b/packages/inter-protocol/test/vaultFactory/vault-contract-wrapper.js
index d79d9b5a16b..e403f71029f 100644
--- a/packages/inter-protocol/test/vaultFactory/vault-contract-wrapper.js
+++ b/packages/inter-protocol/test/vaultFactory/vault-contract-wrapper.js
@@ -1,14 +1,12 @@
 /** @file DEPRECATED use the vault test driver instead */
 import { AmountMath, makeIssuerKit } from '@agoric/ertp';
 
-import { assert } from '@agoric/assert';
 import { makePublishKit, observeNotifier } from '@agoric/notifier';
 import {
   makeFakeMarshaller,
   makeFakeStorage,
 } from '@agoric/notifier/tools/testSupports.js';
 import {
-  atomicRearrange,
   prepareRecorderKit,
   unitAmount,
 } from '@agoric/zoe/src/contractSupport/index.js';
@@ -101,14 +99,14 @@ export async function start(zcf, privateArgs, baggage) {
   const mintAndTransfer = (mintReceiver, toMint, fee, nonMintTransfers) => {
     const kept = AmountMath.subtract(toMint, fee);
     stableMint.mintGains(harden({ Minted: toMint }), mintSeat);
-    /** @type {import('@agoric/zoe/src/contractSupport/atomicTransfer.js').TransferPart[]} */
+    /** @type {TransferPart[]} */
     const transfers = [
       ...nonMintTransfers,
       [mintSeat, vaultFactorySeat, { Minted: fee }],
       [mintSeat, mintReceiver, { Minted: kept }],
     ];
     try {
-      atomicRearrange(zcf, harden(transfers));
+      zcf.atomicRearrange(harden(transfers));
     } catch (e) {
       console.error('mintAndTransfer caught', e);
       stableMint.burnLosses(harden({ Minted: toMint }), mintSeat);
diff --git a/packages/zoe/package.json b/packages/zoe/package.json
index 53d426bd435..3b5e125c6b2 100644
--- a/packages/zoe/package.json
+++ b/packages/zoe/package.json
@@ -104,6 +104,7 @@
       "test/unitTests/zcf/test-reallocate-empty.js",
       "test/unitTests/zcf/test-zoeHelpersWZcf.js",
       "test/unitTests/zcf/test-reallocateForZCFMint.js",
+      "test/unitTests/zcf/test-atomicRearrange.js",
       "test/unitTests/zcf/test-zcf.js",
       "test/unitTests/zcf/test-allStagedSeatsUsed.js",
       "# ManualTimer.setWakeup: no function",
diff --git a/packages/zoe/src/contractFacet/reallocate.js b/packages/zoe/src/contractFacet/reallocate.js
new file mode 100644
index 00000000000..f09b7f031c4
--- /dev/null
+++ b/packages/zoe/src/contractFacet/reallocate.js
@@ -0,0 +1,94 @@
+import { makeScalarMapStore } from '@agoric/vat-data';
+
+import { assertRightsConserved } from './rightsConservation.js';
+import { addToAllocation, subtractFromAllocation } from './allocationMath.js';
+
+const { Fail } = assert;
+
+/** @typedef {Array<AmountKeywordRecord>} TransactionList */
+
+/**
+ * Convert from a list of transfer descriptions ([fromSeat, toSeat, fromAmount,
+ * toAmount], with many parts optional) to a list of resulting allocations for
+ * each of the seats mentioned.
+ *
+ * @param {Array<TransferPart>} transfers
+ * @returns {[ZCFSeat, AmountKeywordRecord][]}
+ */
+export const makeAllocationMap = transfers => {
+  /** @type {MapStore<ZCFSeat, [TransactionList, TransactionList]>} */
+  const allocations = makeScalarMapStore();
+
+  const getAllocations = seat => {
+    if (allocations.has(seat)) {
+      return allocations.get(seat);
+    }
+
+    /** @type {[TransactionList, TransactionList]} */
+    const pair = [[], []];
+    allocations.init(seat, pair);
+    return pair;
+  };
+
+  const decrementAllocation = (seat, decrement) => {
+    const [incr, decr] = getAllocations(seat);
+
+    const newDecr = [...decr, decrement];
+    allocations.set(seat, [incr, newDecr]);
+  };
+
+  const incrementAllocation = (seat, increment) => {
+    const [incr, decr] = getAllocations(seat);
+
+    const newIncr = [...incr, increment];
+    allocations.set(seat, [newIncr, decr]);
+  };
+
+  for (const [fromSeat, toSeat, fromAmounts, toAmounts] of transfers) {
+    if (fromSeat) {
+      if (!fromAmounts) {
+        throw Fail`Transfer from ${fromSeat} must say how much`;
+      }
+      decrementAllocation(fromSeat, fromAmounts);
+      if (toSeat) {
+        // Conserved transfer between seats
+        if (toAmounts) {
+          // distinct amounts, so we check conservation.
+          assertRightsConserved(
+            Object.values(fromAmounts),
+            Object.values(toAmounts),
+          );
+          incrementAllocation(toSeat, toAmounts);
+        } else {
+          // fromAmounts will be used for toAmounts as well
+          incrementAllocation(toSeat, fromAmounts);
+        }
+      } else {
+        // Transfer only from fromSeat
+        !toAmounts ||
+          Fail`Transfer without toSeat cannot have toAmounts ${toAmounts}`;
+      }
+    } else {
+      toSeat || Fail`Transfer must have at least one of fromSeat or toSeat`;
+      // Transfer only to toSeat
+      !fromAmounts ||
+        Fail`Transfer without fromSeat cannot have fromAmounts ${fromAmounts}`;
+      toAmounts || Fail`Transfer to ${toSeat} must say how much`;
+      incrementAllocation(toSeat, toAmounts);
+    }
+  }
+
+  /** @type {[ZCFSeat,AmountKeywordRecord][]} */
+  const resultingAllocations = [];
+  for (const [seat, [incrList, decrList]] of allocations.entries()) {
+    let newAlloc = seat.getCurrentAllocation();
+    for (const incr of incrList) {
+      newAlloc = addToAllocation(newAlloc, incr);
+    }
+    for (const decr of decrList) {
+      newAlloc = subtractFromAllocation(newAlloc, decr);
+    }
+    resultingAllocations.push([seat, newAlloc]);
+  }
+  return resultingAllocations;
+};
diff --git a/packages/zoe/src/contractFacet/types.js b/packages/zoe/src/contractFacet/types.js
index dd86a4c1a04..f6277e641eb 100644
--- a/packages/zoe/src/contractFacet/types.js
+++ b/packages/zoe/src/contractFacet/types.js
@@ -26,6 +26,7 @@
  * synchronously from within the contract, and usually is referred to
  * in code as zcf.
  *
+ * @property {(transfers: TransferPart[]) => void} atomicRearrange - atomically reallocate amounts among seats.
  * @property {Reallocate} reallocate - reallocate amounts among seats.
  * Deprecated: Use atomicRearrange instead.
  * @property {(keyword: Keyword) => void} assertUniqueKeyword - check
@@ -59,6 +60,8 @@
  */
 
 /**
+ * @deprecated reallocate(). Use zcf.atomicRearrange() instead
+ *
  * @typedef {(seat1: ZCFSeat, seat2: ZCFSeat, ...seatRest:
  * Array<ZCFSeat>) => void} Reallocate
  *
@@ -83,6 +86,15 @@
  * effect offer safety for seats whose allocations change.
  */
 
+/**
+ * @typedef {[
+ *   fromSeat?: ZCFSeat,
+ *   toSeat?: ZCFSeat,
+ *   fromAmounts?: AmountKeywordRecord,
+ *   toAmounts?: AmountKeywordRecord
+ * ]} TransferPart
+ */
+
 /**
  * @callback SaveIssuer
  *
diff --git a/packages/zoe/src/contractFacet/zcfSeat.js b/packages/zoe/src/contractFacet/zcfSeat.js
index a7caa360852..006ea2840cb 100644
--- a/packages/zoe/src/contractFacet/zcfSeat.js
+++ b/packages/zoe/src/contractFacet/zcfSeat.js
@@ -1,10 +1,10 @@
 import {
   makeScalarBigWeakMapStore,
-  provideDurableMapStore,
-  provideDurableWeakMapStore,
+  prepareExoClass,
   prepareExoClassKit,
   provide,
-  prepareExoClass,
+  provideDurableMapStore,
+  provideDurableWeakMapStore,
 } from '@agoric/vat-data';
 import { E } from '@endo/eventual-send';
 import { AmountMath } from '@agoric/ertp';
@@ -19,6 +19,8 @@ import {
   SeatDataShape,
   SeatShape,
 } from '../typeGuards.js';
+import { makeAllocationMap } from './reallocate.js';
+import { TransferPartShape } from '../contractSupport/atomicTransfer.js';
 
 const { Fail } = assert;
 
@@ -214,6 +216,10 @@ export const createSeatManager = (
 
         return isOfferSafe(state.proposal, reallocation);
       },
+      /**
+       * @deprecated switch to zcf.atomicRearrange()
+       * @param {AmountKeywordRecord} amountKeywordRecord
+       */
       incrementBy(amountKeywordRecord) {
         const { self } = this;
         assertActive(self);
@@ -227,6 +233,10 @@ export const createSeatManager = (
         );
         return amountKeywordRecord;
       },
+      /**
+       * @deprecated switch to zcf.atomicRearrange()
+       * @param {AmountKeywordRecord} amountKeywordRecord
+       */
       decrementBy(amountKeywordRecord) {
         const { self } = this;
         assertActive(self);
@@ -265,6 +275,7 @@ export const createSeatManager = (
   const ZcfSeatManagerIKit = harden({
     seatManager: M.interface('ZcfSeatManager', {
       makeZCFSeat: M.call(SeatDataShape).returns(M.remotable('zcfSeat')),
+      atomicRearrange: M.call(M.arrayOf(TransferPartShape)).returns(),
       reallocate: M.call(M.remotable('zcfSeat'), M.remotable('zcfSeat'))
         .rest(M.arrayOf(M.remotable('zcfSeat')))
         .returns(),
@@ -289,6 +300,96 @@ export const createSeatManager = (
           return zcfSeat;
         },
 
+        /**
+         * Rearrange the allocations according to the transfer descriptions.
+         * This is a set of changes to allocations that must satisfy several
+         * constraints. If these constraints are all met, then the reallocation
+         * happens atomically. Otherwise, it does not happen at all.
+         *
+         * The conditions
+         *    * All the mentioned seats are still live,
+         *    * No outstanding stagings for any of the mentioned seats. Stagings
+         *      have been deprecated in favor or atomicRearrange. To prevent
+         *      confusion, for each reallocation, it can only be expressed in
+         *      the old way or the new way, but not a mixture.
+         *    * Offer safety
+         *    * Overall conservation
+         *
+         * The overall transfer is expressed as an array of `TransferPart`. Each
+         * individual `TransferPart` is one of
+         * - A transfer from a `fromSeat` to a `toSeat`. Specify both toAmount
+         *     and fromAmount to change keywords, otherwise only fromAmount is required.
+         * - A taking from a `fromSeat`'s allocation. See the `fromOnly` helper.
+         * - A giving into a `toSeat`'s allocation. See the `toOnly` helper.
+         *
+         * @param {TransferPart[]} transfers
+         */
+        atomicRearrange(transfers) {
+          const newAllocations = makeAllocationMap(transfers);
+
+          // ////// All Seats are active /////////////////////////////////
+          for (const [seat] of newAllocations) {
+            assertActive(seat);
+            !seat.hasStagedAllocation() ||
+              Fail`Cannot mix atomicRearrange with seat stagings: ${seat}`;
+            zcfSeatToSeatHandle.has(seat) ||
+              Fail`The seat ${seat} was not recognized`;
+          }
+
+          // ////// Ensure that rights are conserved overall /////////////
+
+          // convert array of keywordAmountRecords to 1-level array of Amounts
+          const flattenAmounts = allocations =>
+            allocations.flatMap(Object.values);
+          const previousAmounts = flattenAmounts(
+            newAllocations.map(([seat]) => seat.getCurrentAllocation()),
+          );
+          const newAmounts = flattenAmounts(
+            newAllocations.map(([_, allocation]) => allocation),
+          );
+          assertRightsConserved(previousAmounts, newAmounts);
+
+          // ////// Ensure that offer safety holds ///////////////////////
+          for (const [seat, allocation] of newAllocations) {
+            isOfferSafe(seat.getProposal(), allocation) ||
+              Fail`Offer safety was violated by the proposed allocation: ${allocation}. Proposal was ${seat.getProposal()}`;
+          }
+
+          const seatHandleAllocations = newAllocations.map(
+            ([seat, allocation]) => {
+              const seatHandle = zcfSeatToSeatHandle.get(seat);
+              return { allocation, seatHandle };
+            },
+          );
+          try {
+            // No side effects above. All conditions checked which could have
+            // caused us to reject this reallocation. Notice that the current
+            // allocations are captured in seatHandleAllocations, so there must
+            // be no awaits between that assignment and here.
+            //
+            // COMMIT POINT
+            //
+            // The effects must succeed atomically. The call to
+            // replaceAllocations() will be processed in the order of updates
+            // from ZCF to Zoe. Its effects must occur immediately in Zoe on
+            // reception, and must not fail.
+            //
+            // Commit the new allocations (currentAllocation is replaced
+            // for each of the seats) and inform Zoe of the new allocation.
+
+            for (const [seat, allocation] of newAllocations) {
+              activeZCFSeats.set(seat, allocation);
+            }
+
+            // we don't wait for the results here. As described in
+            // docs/zoe-zcf.md, The initial allocation to a seat originates with
+            // Zoe, but *all subsequent updates come from ZCF to Zoe*.
+            void E(zoeInstanceAdmin).replaceAllocations(seatHandleAllocations);
+          } catch (err) {
+            shutdownWithFailure(err);
+            throw err;
+          }
+        },
         reallocate(/** @type {ZCFSeat[]} */ ...seats) {
           seats.forEach(assertActive);
           seats.forEach(assertStagedAllocation);
diff --git a/packages/zoe/src/contractFacet/zcfZygote.js b/packages/zoe/src/contractFacet/zcfZygote.js
index cc09e66f095..8b444299dd2 100644
--- a/packages/zoe/src/contractFacet/zcfZygote.js
+++ b/packages/zoe/src/contractFacet/zcfZygote.js
@@ -251,6 +251,7 @@ export const makeZCFZygote = async (
   // accept raw functions. assert cannot be a valid passable! (It's a function
   // and has members.)
   const zcf = Remotable('Alleged: zcf', undefined, {
+    atomicRearrange: transfers => seatManager.atomicRearrange(transfers),
     reallocate: (...seats) => seatManager.reallocate(...seats),
     assertUniqueKeyword: kwd => getInstanceRecHolder().assertUniqueKeyword(kwd),
     saveIssuer: async (issuerP, keyword) => {
diff --git a/packages/zoe/src/contractSupport/atomicTransfer.js b/packages/zoe/src/contractSupport/atomicTransfer.js
index fa27fe8adc7..befda09311c 100644
--- a/packages/zoe/src/contractSupport/atomicTransfer.js
+++ b/packages/zoe/src/contractSupport/atomicTransfer.js
@@ -1,23 +1,11 @@
-import { mustMatch, M } from '@agoric/store';
-import { assertRightsConserved } from '../contractFacet/rightsConservation.js';
+import { M } from '@agoric/store';
 import { AmountKeywordRecordShape, SeatShape } from '../typeGuards.js';
 
-const { Fail, quote: q } = assert;
-
 export const TransferPartShape = M.splitArray(
   harden([M.opt(SeatShape), M.opt(SeatShape), M.opt(AmountKeywordRecordShape)]),
   harden([M.opt(AmountKeywordRecordShape)]),
 );
 
-/**
- * @typedef {[
- *   fromSeat?: ZCFSeat,
- *   toSeat?: ZCFSeat,
- *   fromAmounts?: AmountKeywordRecord,
- *   toAmounts?: AmountKeywordRecord
- * ]} TransferPart
- */
-
 /**
  * Asks Zoe (via zcf) to rearrange the allocations among the seats
  * mentioned. This is a set of changes to allocations that must satisfy
@@ -52,86 +40,13 @@ export const TransferPartShape = M.splitArray(
  * which will remain helpers. These helper are for convenience
  * in expressing atomic rearrangements clearly.
  *
+ * @deprecated use the zcf builtin instead
+ *
  * @param {ZCF} zcf
  * @param {TransferPart[]} transfers
  */
 export const atomicRearrange = (zcf, transfers) => {
-  mustMatch(transfers, M.arrayOf(M.array()), 'transfers');
-  const uniqueSeatSet = new Set();
-  for (const [
-    fromSeat = undefined,
-    toSeat = undefined,
-    fromAmounts = undefined,
-    toAmounts = undefined,
-  ] of transfers) {
-    if (fromSeat) {
-      if (!fromAmounts) {
-        throw Fail`Transfer from ${fromSeat} must say how much`;
-      }
-      uniqueSeatSet.add(fromSeat);
-      if (toSeat) {
-        // Conserved transfer between seats
-        if (toAmounts) {
-          // distinct amounts, so we check conservation.
-          assertRightsConserved(
-            Object.values(fromAmounts),
-            Object.values(toAmounts),
-          );
-        } // else fromAmounts will be used as toAmounts
-        uniqueSeatSet.add(toSeat);
-      } else {
-        // Transfer only from fromSeat
-        !toAmounts ||
-          Fail`Transfer without toSeat cannot have toAmounts ${toAmounts}`;
-      }
-    } else {
-      toSeat || Fail`Transfer must have at least one of fromSeat or toSeat`;
-      // Transfer only to toSeat
-      !fromAmounts ||
-        Fail`Transfer without fromSeat cannot have fromAmounts ${fromAmounts}`;
-      toAmounts || Fail`Transfer to ${toSeat} must say how much`;
-      uniqueSeatSet.add(toSeat);
-    }
-  }
-
-  const uniqueSeats = harden([...uniqueSeatSet.keys()]);
-  for (const seat of uniqueSeats) {
-    !seat.hasStagedAllocation() ||
-      Fail`Cannot mix atomicRearrange with seat stagings: ${seat}`;
-  }
-
-  // At this point the basic shape has been validated
-
-  try {
-    for (const [
-      fromSeat = undefined,
-      toSeat = undefined,
-      fromAmounts = undefined,
-      toAmounts = toSeat && fromAmounts,
-    ] of transfers) {
-      if (fromSeat && fromAmounts) {
-        // testing both just to satisfy the type checker
-        fromSeat.decrementBy(fromAmounts);
-      }
-      if (toSeat && toAmounts) {
-        // testing both just to satisfy the type checker
-        toSeat.incrementBy(toAmounts);
-      }
-    }
-
-    // Perhaps deprecate this >= 2 restriction?
-    uniqueSeats.length >= 2 ||
-      Fail`Can only commit a reallocation among at least 2 seats: ${q(
-        uniqueSeats.length,
-      )}`;
-    // Take it apart and put it back together to satisfy the type checker
-    const [seat0, seat1, ...restSeats] = uniqueSeats;
-    zcf.reallocate(seat0, seat1, ...restSeats);
-  } finally {
-    for (const seat of uniqueSeats) {
-      seat.clear();
-    }
-  }
+  zcf.atomicRearrange(transfers);
 };
 
 /**
@@ -179,4 +94,4 @@ export const atomicTransfer = (
   toSeat = undefined,
   fromAmounts = undefined,
   toAmounts = undefined,
-) => atomicRearrange(zcf, harden([[fromSeat, toSeat, fromAmounts, toAmounts]]));
+) => zcf.atomicRearrange(harden([[fromSeat, toSeat, fromAmounts, toAmounts]]));
diff --git a/packages/zoe/src/contractSupport/zoeHelpers.js b/packages/zoe/src/contractSupport/zoeHelpers.js
index 8eee34c1aa5..2287395c33f 100644
--- a/packages/zoe/src/contractSupport/zoeHelpers.js
+++ b/packages/zoe/src/contractSupport/zoeHelpers.js
@@ -4,12 +4,7 @@ import { makePromiseKit } from '@endo/promise-kit';
 import { AssetKind } from '@agoric/ertp';
 import { fromUniqueEntries } from '@agoric/internal';
 import { satisfiesWant } from '../contractFacet/offerSafety.js';
-import {
-  atomicRearrange,
-  atomicTransfer,
-  fromOnly,
-  toOnly,
-} from './atomicTransfer.js';
+import { atomicTransfer, fromOnly, toOnly } from './atomicTransfer.js';
 
 export const defaultAcceptanceMsg = `The offer has been accepted. Once the contract has been completed, please check your payout`;
 
@@ -57,8 +52,7 @@ export const satisfies = (zcf, seat, update) => {
 /** @type {Swap} */
 export const swap = (zcf, leftSeat, rightSeat) => {
   try {
-    atomicRearrange(
-      zcf,
+    zcf.atomicRearrange(
       harden([
         [rightSeat, leftSeat, leftSeat.getProposal().want],
         [leftSeat, rightSeat, rightSeat.getProposal().want],
@@ -78,8 +72,7 @@ export const swap = (zcf, leftSeat, rightSeat) => {
 /** @type {SwapExact} */
 export const swapExact = (zcf, leftSeat, rightSeat) => {
   try {
-    atomicRearrange(
-      zcf,
+    zcf.atomicRearrange(
       harden([
         fromOnly(rightSeat, rightSeat.getProposal().give),
         fromOnly(leftSeat, leftSeat.getProposal().give),
diff --git a/packages/zoe/src/contracts/auction/firstPriceLogic.js b/packages/zoe/src/contracts/auction/firstPriceLogic.js
index 294a3837ed4..d44239b37c6 100644
--- a/packages/zoe/src/contracts/auction/firstPriceLogic.js
+++ b/packages/zoe/src/contracts/auction/firstPriceLogic.js
@@ -1,5 +1,4 @@
 import { AmountMath } from '@agoric/ertp';
-import { atomicRearrange } from '../../contractSupport/index.js';
 
 /**
  * @param {ZCF} zcf
@@ -42,8 +41,7 @@ export const calcWinnerAndClose = (zcf, sellSeat, bidSeats) => {
   }
 
   // Everyone else gets a refund so their values remain the same.
-  atomicRearrange(
-    zcf,
+  zcf.atomicRearrange(
     harden([
       [highestBidSeat, sellSeat, { Bid: highestBid }, { Ask: highestBid }],
       [sellSeat, highestBidSeat, { Asset: assetAmount }],
diff --git a/packages/zoe/src/contracts/auction/secondPriceLogic.js b/packages/zoe/src/contracts/auction/secondPriceLogic.js
index 29d1faca8fc..7d08cbc1b20 100644
--- a/packages/zoe/src/contracts/auction/secondPriceLogic.js
+++ b/packages/zoe/src/contracts/auction/secondPriceLogic.js
@@ -1,5 +1,4 @@
 import { AmountMath } from '@agoric/ertp';
-import { atomicRearrange } from '../../contractSupport/index.js';
 
 /**
  * @param {ZCF} zcf
@@ -48,8 +47,7 @@ export const calcWinnerAndClose = (zcf, sellSeat, bidSeats) => {
   }
 
   // Everyone else gets a refund so their values remain the same.
-  atomicRearrange(
-    zcf,
+  zcf.atomicRearrange(
     harden([
       [
         highestBidSeat,
diff --git a/packages/zoe/src/contracts/autoswap.js b/packages/zoe/src/contracts/autoswap.js
index 6d717ae153c..1b9f58f40a3 100644
--- a/packages/zoe/src/contracts/autoswap.js
+++ b/packages/zoe/src/contracts/autoswap.js
@@ -11,7 +11,6 @@ import {
   assertProposalShape,
   assertNatAssetKind,
   calcSecondaryRequired,
-  atomicRearrange,
 } from '../contractSupport/index.js';
 
 /**
@@ -88,8 +87,7 @@ const start = async zcf => {
   };
 
   function consummate(tradeAmountIn, tradeAmountOut, swapSeat) {
-    atomicRearrange(
-      zcf,
+    zcf.atomicRearrange(
       harden([
         [
           swapSeat,
@@ -205,8 +203,7 @@ const start = async zcf => {
       Central: AmountMath.make(brands.Central, centralIn),
       Secondary: secondaryAmount,
     };
-    atomicRearrange(
-      zcf,
+    zcf.atomicRearrange(
       harden([
         [seat, poolSeat, liquidityDeposited],
         [poolSeat, seat, { Liquidity: liquidityAmountOut }],
@@ -308,8 +305,7 @@ const start = async zcf => {
       Secondary: newUserSecondaryAmount,
     };
 
-    atomicRearrange(
-      zcf,
+    zcf.atomicRearrange(
       harden([
         [removeLiqSeat, poolSeat, { Liquidity: userAllocation.Liquidity }],
         [poolSeat, removeLiqSeat, liquidityRemoved],
diff --git a/packages/zoe/src/contracts/barterExchange.js b/packages/zoe/src/contracts/barterExchange.js
index 2ed71f86de1..5320359e212 100644
--- a/packages/zoe/src/contracts/barterExchange.js
+++ b/packages/zoe/src/contracts/barterExchange.js
@@ -1,7 +1,7 @@
 import { Far } from '@endo/marshal';
 import { makeLegacyMap } from '@agoric/store';
 // Eventually will be importable from '@agoric/zoe-contract-support'
-import { satisfies, atomicRearrange } from '../contractSupport/index.js';
+import { satisfies } from '../contractSupport/index.js';
 
 /**
  * This Barter Exchange accepts offers to trade arbitrary goods for other
@@ -63,8 +63,7 @@ const start = zcf => {
     const matchingTrade = findMatchingTrade(offerDetails, orders);
     if (matchingTrade) {
       // reallocate by giving each side what it wants
-      atomicRearrange(
-        zcf,
+      zcf.atomicRearrange(
         harden([
           [
             offerDetails.seat,
diff --git a/packages/zoe/src/contracts/callSpread/fundedCallSpread.js b/packages/zoe/src/contracts/callSpread/fundedCallSpread.js
index 28d965687b9..c15ba721f34 100644
--- a/packages/zoe/src/contracts/callSpread/fundedCallSpread.js
+++ b/packages/zoe/src/contracts/callSpread/fundedCallSpread.js
@@ -7,7 +7,6 @@ import {
   assertProposalShape,
   depositToSeat,
   assertNatAssetKind,
-  atomicRearrange,
 } from '../../contractSupport/index.js';
 import { makePayoffHandler } from './payoffHandler.js';
 import { Position } from './position.js';
@@ -112,8 +111,7 @@ const start = async zcf => {
         give: { Collateral: null },
         want: { LongOption: null, ShortOption: null },
       });
-      atomicRearrange(
-        zcf,
+      zcf.atomicRearrange(
         harden([
           [creatorSeat, collateralSeat, { Collateral: settlementAmount }],
           [
diff --git a/packages/zoe/src/contracts/callSpread/pricedCallSpread.js b/packages/zoe/src/contracts/callSpread/pricedCallSpread.js
index 10add08117a..9b06e16fd25 100644
--- a/packages/zoe/src/contracts/callSpread/pricedCallSpread.js
+++ b/packages/zoe/src/contracts/callSpread/pricedCallSpread.js
@@ -10,7 +10,6 @@ import {
   assertNatAssetKind,
   makeRatio,
   ceilMultiplyBy,
-  atomicRearrange,
 } from '../../contractSupport/index.js';
 import { makePayoffHandler } from './payoffHandler.js';
 import { Position } from './position.js';
@@ -132,8 +131,7 @@ const start = zcf => {
         'wanted option not a match',
       );
 
-      atomicRearrange(
-        zcf,
+      zcf.atomicRearrange(
         harden([
           [collateralSeat, depositSeat, spreadAmount],
           [depositSeat, collateralSeat, { Collateral: newCollateral }],
diff --git a/packages/zoe/src/contracts/loan/borrow.js b/packages/zoe/src/contracts/loan/borrow.js
index a50285d6c37..f24a039ed26 100644
--- a/packages/zoe/src/contracts/loan/borrow.js
+++ b/packages/zoe/src/contracts/loan/borrow.js
@@ -9,7 +9,6 @@ import {
   getAmountOut,
   ceilMultiplyBy,
   getTimestamp,
-  atomicRearrange,
 } from '../../contractSupport/index.js';
 
 import { scheduleLiquidation } from './scheduleLiquidation.js';
@@ -72,8 +71,7 @@ export const makeBorrowInvitation = (zcf, config) => {
 
     const { zcfSeat: collateralSeat } = zcf.makeEmptySeatKit();
 
-    atomicRearrange(
-      zcf,
+    zcf.atomicRearrange(
       harden([
         // Transfer the wanted Loan amount to the borrower
         [lenderSeat, borrowerSeat, { Loan: loanWanted }],
diff --git a/packages/zoe/src/contracts/loan/close.js b/packages/zoe/src/contracts/loan/close.js
index 2351817758b..2d7060befb8 100644
--- a/packages/zoe/src/contracts/loan/close.js
+++ b/packages/zoe/src/contracts/loan/close.js
@@ -3,10 +3,7 @@ import './types.js';
 import { Fail } from '@agoric/assert';
 import { AmountMath } from '@agoric/ertp';
 
-import {
-  assertProposalShape,
-  atomicRearrange,
-} from '../../contractSupport/index.js';
+import { assertProposalShape } from '../../contractSupport/index.js';
 
 // The debt, the amount which must be repaid, is just the amount
 // loaned plus interest (aka stability fee). All debt must be repaid
@@ -44,8 +41,7 @@ export const makeCloseLoanInvitation = (zcf, config) => {
       'Collateral',
       collateralBrand,
     );
-    atomicRearrange(
-      zcf,
+    zcf.atomicRearrange(
       harden([
         [collateralSeat, repaySeat, { Collateral: collateralAmount }],
         [repaySeat, lenderSeat, { Loan: debt }],
diff --git a/packages/zoe/src/contracts/sellItems.js b/packages/zoe/src/contracts/sellItems.js
index 77b43ade259..7ec99d2da9b 100644
--- a/packages/zoe/src/contracts/sellItems.js
+++ b/packages/zoe/src/contracts/sellItems.js
@@ -11,7 +11,6 @@ import {
   defaultAcceptanceMsg,
   assertProposalShape,
   assertNatAssetKind,
-  atomicRearrange,
 } from '../contractSupport/index.js';
 
 const { Fail } = assert;
@@ -107,8 +106,7 @@ const start = zcf => {
       Fail`More money (${totalCost}) is required to buy these items`;
 
     // Reallocate.
-    atomicRearrange(
-      zcf,
+    zcf.atomicRearrange(
       harden([
         [buyerSeat, sellerSeat, { Money: providedMoney }],
         [sellerSeat, buyerSeat, { Items: wantedItems }],
diff --git a/packages/zoe/test/unitTests/contracts/loan/test-liquidate.js b/packages/zoe/test/unitTests/contracts/loan/test-liquidate.js
index d6f2e79c90d..4a321559beb 100644
--- a/packages/zoe/test/unitTests/contracts/loan/test-liquidate.js
+++ b/packages/zoe/test/unitTests/contracts/loan/test-liquidate.js
@@ -11,7 +11,6 @@ import {
   checkNoNewOffers,
   checkPayouts,
 } from './helpers.js';
-import { atomicRearrange } from '../../../../src/contractSupport/atomicTransfer.js';
 
 test('test doLiquidation with mocked autoswap', async t => {
   const { zcf, collateralKit, loanKit } = await setupLoanUnitTest();
@@ -43,8 +42,7 @@ test('test doLiquidation with mocked autoswap', async t => {
 
   const swapHandler = swapSeat => {
     // swapSeat gains 20 loan tokens from fakePoolSeat, loses all collateral
-    atomicRearrange(
-      zcf,
+    zcf.atomicRearrange(
       harden([
         [swapSeat, fakePoolSeat, { In: collateral }, { Secondary: collateral }],
         [fakePoolSeat, swapSeat, { Central: price }, { Out: price }],
diff --git a/packages/zoe/test/unitTests/zcf/test-atomicRearrange.js b/packages/zoe/test/unitTests/zcf/test-atomicRearrange.js
new file mode 100644
index 00000000000..80de4f34aba
--- /dev/null
+++ b/packages/zoe/test/unitTests/zcf/test-atomicRearrange.js
@@ -0,0 +1,268 @@
+// eslint-disable-next-line import/no-extraneous-dependencies
+import { test } from '@agoric/zoe/tools/prepare-test-env-ava.js';
+
+import { AmountMath } from '@agoric/ertp';
+import {
+  fromOnly,
+  toOnly,
+} from '../../../src/contractSupport/atomicTransfer.js';
+
+import { setupZCFTest } from './setupZcfTest.js';
+import { makeOffer } from '../makeOffer.js';
+import { setup } from '../setupBasicMints.js';
+
+const zcfMintUtils = async (zcf, name) => {
+  const mint = await zcf.makeZCFMint(name);
+  const { brand } = mint.getIssuerRecord();
+
+  return {
+    make: v => AmountMath.make(brand, v),
+    makeEmpty: () => AmountMath.makeEmpty(brand),
+    brand: () => brand,
+    mintGains: (seat, v, t) =>
+      mint.mintGains(harden({ [t]: AmountMath.make(brand, v) }), seat),
+  };
+};
+
+const assertAllocations = (t, seat, expectedAllocations) => {
+  const allocations = seat.getCurrentAllocation();
+  t.deepEqual(allocations, expectedAllocations, 'allocations did not match');
+};
+
+test(`zcf.atomicRearrange all Legal Combinations`, async t => {
+  const { zcf } = await setupZCFTest();
+  const moola = await zcfMintUtils(zcf, 'Moola');
+  const bucks = await zcfMintUtils(zcf, 'Bucks');
+
+  const { zcfSeat: alice } = zcf.makeEmptySeatKit();
+  const { zcfSeat: bob } = zcf.makeEmptySeatKit();
+  const { zcfSeat: carol } = zcf.makeEmptySeatKit();
+
+  moola.mintGains(alice, 100n, 'M');
+  bucks.mintGains(bob, 50n, 'B');
+
+  zcf.atomicRearrange([
+    [alice, bob, { M: moola.make(20n) }],
+    [bob, carol, { B: bucks.make(30n) }],
+    [alice, carol, { M: moola.make(15n) }, { C: moola.make(15n) }],
+    fromOnly(bob, { B: bucks.make(12n) }),
+    toOnly(alice, { N: bucks.make(12n) }),
+  ]);
+  assertAllocations(t, alice, { M: moola.make(65n), N: bucks.make(12n) });
+  assertAllocations(t, bob, { B: bucks.make(8n), M: moola.make(20n) });
+  assertAllocations(t, carol, { B: bucks.make(30n), C: moola.make(15n) });
+});
+
+test(`zcf.atomicRearrange missing to amount`, async t => {
+  const { zcf } = await setupZCFTest();
+  const moola = await zcfMintUtils(zcf, 'Moola');
+  const bucks = await zcfMintUtils(zcf, 'Bucks');
+
+  const { zcfSeat: alice } = zcf.makeEmptySeatKit();
+  const { zcfSeat: bob } = zcf.makeEmptySeatKit();
+  const { zcfSeat: carol } = zcf.makeEmptySeatKit();
+
+  moola.mintGains(alice, 100n, 'M');
+  bucks.mintGains(bob, 50n, 'B');
+
+  t.throws(() => zcf.atomicRearrange([[undefined, carol, undefined]]), {
+    message: /must say how much/,
+  });
+});
+
+test(`zcf.atomicRearrange too few argumemnts`, async t => {
+  const { zcf } = await setupZCFTest();
+  const moola = await zcfMintUtils(zcf, 'Moola');
+  const bucks = await zcfMintUtils(zcf, 'Bucks');
+
+  const { zcfSeat: alice } = zcf.makeEmptySeatKit();
+  const { zcfSeat: bob } = zcf.makeEmptySeatKit();
+
+  moola.mintGains(alice, 100n, 'M');
+  bucks.mintGains(bob, 50n, 'B');
+
+  t.throws(
+    () =>
+      zcf.atomicRearrange([
+        [alice, bob, { M: moola.make(20n) }],
+        // @ts-expect-error Testing
+        [bob, { B: bucks.make(30n) }],
+      ]),
+    { message: /Expected at least 3 arguments/ },
+  );
+});
+
+test(`zcf.atomicRearrange no seats`, async t => {
+  const { zcf } = await setupZCFTest();
+  const moola = await zcfMintUtils(zcf, 'Moola');
+  const bucks = await zcfMintUtils(zcf, 'Bucks');
+
+  const { zcfSeat: alice } = zcf.makeEmptySeatKit();
+  const { zcfSeat: bob } = zcf.makeEmptySeatKit();
+
+  moola.mintGains(alice, 100n, 'M');
+  bucks.mintGains(bob, 50n, 'B');
+
+  t.throws(
+    () =>
+      zcf.atomicRearrange([
+        [alice, bob, { M: moola.make(20n) }],
+        [undefined, undefined, { B: bucks.make(30n) }],
+      ]),
+    { message: /Transfer must have at least one of fromSeat or toSeat/ },
+  );
+});
+
+test(`zcf.atomicRearrange no transfers`, async t => {
+  const { zcf } = await setupZCFTest();
+  const moola = await zcfMintUtils(zcf, 'Moola');
+  const bucks = await zcfMintUtils(zcf, 'Bucks');
+
+  const { zcfSeat: alice } = zcf.makeEmptySeatKit();
+  const { zcfSeat: bob } = zcf.makeEmptySeatKit();
+
+  moola.mintGains(alice, 100n, 'M');
+  bucks.mintGains(bob, 50n, 'B');
+
+  t.throws(
+    () =>
+      zcf.atomicRearrange([
+        [alice, bob, { M: moola.make(20n) }],
+        // @ts-expect-error Testing
+        [bob, alice, bob],
+      ]),
+    { message: /Must be a copyRecord/ },
+  );
+
+  t.throws(
+    () =>
+      zcf.atomicRearrange([
+        [alice, bob, { M: moola.make(20n) }],
+        [bob, alice, undefined, undefined],
+      ]),
+    { message: / must say how much/ },
+  );
+});
+
+test(`zcf.atomicRearrange no FromAmount`, async t => {
+  const { zcf } = await setupZCFTest();
+  const moola = await zcfMintUtils(zcf, 'Moola');
+  const bucks = await zcfMintUtils(zcf, 'Bucks');
+
+  const { zcfSeat: alice } = zcf.makeEmptySeatKit();
+  const { zcfSeat: bob } = zcf.makeEmptySeatKit();
+
+  moola.mintGains(alice, 100n, 'M');
+  bucks.mintGains(bob, 50n, 'B');
+
+  t.throws(
+    () =>
+      zcf.atomicRearrange([
+        [alice, bob, { M: moola.make(20n) }],
+        [alice, bob, undefined, { M: moola.make(20n) }],
+      ]),
+    { message: /must say how much/ },
+  );
+});
+
+test(`zcf.atomicRearrange FromAmount w/o fromSeat`, async t => {
+  const { zcf } = await setupZCFTest();
+  const moola = await zcfMintUtils(zcf, 'Moola');
+  const bucks = await zcfMintUtils(zcf, 'Bucks');
+
+  const { zcfSeat: alice } = zcf.makeEmptySeatKit();
+  const { zcfSeat: bob } = zcf.makeEmptySeatKit();
+
+  moola.mintGains(alice, 100n, 'M');
+  bucks.mintGains(bob, 50n, 'B');
+
+  t.throws(
+    () =>
+      zcf.atomicRearrange([
+        [alice, bob, { M: moola.make(20n) }],
+        [undefined, bob, { B: bucks.make(37n) }, { M: moola.make(20n) }],
+      ]),
+    { message: /Transfer without fromSeat cannot have fromAmounts/ },
+  );
+});
+
+test(`zcf.atomicRearrange toAmount w/o toSeat`, async t => {
+  const { zcf } = await setupZCFTest();
+  const moola = await zcfMintUtils(zcf, 'Moola');
+  const bucks = await zcfMintUtils(zcf, 'Bucks');
+
+  const { zcfSeat: alice } = zcf.makeEmptySeatKit();
+  const { zcfSeat: bob } = zcf.makeEmptySeatKit();
+
+  moola.mintGains(alice, 100n, 'M');
+  bucks.mintGains(bob, 50n, 'B');
+
+  t.throws(
+    () =>
+      zcf.atomicRearrange([
+        [alice, bob, { M: moola.make(20n) }],
+        [alice, undefined, { B: bucks.make(37n) }, { M: moola.make(20n) }],
+      ]),
+    { message: /Transfer without toSeat cannot have toAmounts/ },
+  );
+});
+
+test(`zcf.atomicRearrange breaks conservation`, async t => {
+  const { zcf } = await setupZCFTest();
+  const moola = await zcfMintUtils(zcf, 'Moola');
+  const bucks = await zcfMintUtils(zcf, 'Bucks');
+
+  const { zcfSeat: alice } = zcf.makeEmptySeatKit();
+  const { zcfSeat: bob } = zcf.makeEmptySeatKit();
+
+  moola.mintGains(alice, 100n, 'M');
+  bucks.mintGains(bob, 50n, 'B');
+
+  t.throws(
+    () =>
+      zcf.atomicRearrange([
+        [alice, bob, { M: moola.make(20n) }],
+        toOnly(bob, { C: bucks.make(27n) }),
+      ]),
+    { message: /rights were not conserved for brand / },
+  );
+  t.throws(
+    () =>
+      zcf.atomicRearrange([
+        [alice, bob, { M: moola.make(20n) }],
+        fromOnly(bob, { B: bucks.make(10n) }),
+      ]),
+    { message: /rights were not conserved for brand / },
+  );
+});
+
+test(`zcf.atomicRearrange breaks offerSafety`, async t => {
+  const { moolaKit, moola, bucksKit, bucks } = setup();
+  const { zoe, zcf } = await setupZCFTest({
+    M: moolaKit.issuer,
+    B: bucksKit.issuer,
+  });
+
+  const { zcfSeat: alice } = await makeOffer(
+    zoe,
+    zcf,
+    harden({ give: { M: moola(30n) }, want: { B: bucks(200n) } }),
+    harden({ M: moolaKit.mint.mintPayment(moola(30n)) }),
+  );
+
+  const { zcfSeat: bob } = await makeOffer(
+    zoe,
+    zcf,
+    harden({ give: { B: bucks(20n) } }),
+    harden({ B: bucksKit.mint.mintPayment(bucks(20n)) }),
+  );
+
+  t.throws(
+    () =>
+      zcf.atomicRearrange([
+        [bob, alice, { B: bucks(20n) }],
+        [alice, bob, { M: moola(30n) }],
+      ]),
+    { message: /Offer safety was violated/ },
+  );
+});