diff --git a/modules/sdk-coin-canton/src/canton.ts b/modules/sdk-coin-canton/src/canton.ts
index e5ca997604..f414dd42b5 100644
--- a/modules/sdk-coin-canton/src/canton.ts
+++ b/modules/sdk-coin-canton/src/canton.ts
@@ -133,6 +133,7 @@ export class Canton extends BaseCoin {
       case TransactionType.CosignDelegationProposal:
       case TransactionType.AllocationAllocate:
       case TransactionType.AllocationRequest:
+      case TransactionType.EndInvestorOnboardingOffer:
         // There is no recipient info to verify for these transaction types, so always return true.
         return true;
       case TransactionType.CantonCommand:
diff --git a/modules/sdk-coin-canton/src/lib/endInvestorOnboardingOfferBuilder.ts b/modules/sdk-coin-canton/src/lib/endInvestorOnboardingOfferBuilder.ts
new file mode 100644
index 0000000000..3b067c22d0
--- /dev/null
+++ b/modules/sdk-coin-canton/src/lib/endInvestorOnboardingOfferBuilder.ts
@@ -0,0 +1,125 @@
+import { PublicKey, TransactionType } from '@bitgo/sdk-core';
+import { BaseCoin as CoinConfig } from '@bitgo/statics';
+import { CantonPrepareCommandResponse, EndInvestorOnboardingOfferData } from './iface';
+import { TransactionBuilder } from './transactionBuilder';
+import { Transaction } from './transaction/transaction';
+
+/**
+ * Builder for an EndInvestorOnboardingOffer txRequest — an internal, non-signable transaction
+ * that records an on-chain EndInvestorOnboardingOffer contract on the end investor's wallet
+ * so they can accept or reject. Built locally without an IMS call because the inviting
+ * participant may be external (non-BitGo) and therefore not registered in BitGo's IMS.
+ *
+ * setTransaction and addSignature are intentionally not implemented because this
+ * transaction type is never signed or broadcast directly.
+ */
+export class EndInvestorOnboardingOfferBuilder extends TransactionBuilder {
+  private _contractId: string;
+  private _endInvestorPartyId: string;
+  private _participantPartyId: string;
+  private _comment?: string;
+
+  constructor(_coinConfig: Readonly<CoinConfig>) {
+    super(_coinConfig);
+  }
+
+  initBuilder(tx: Transaction): void {
+    super.initBuilder(tx);
+    this.setTransactionType();
+  }
+
+  get transactionType(): TransactionType {
+    return TransactionType.EndInvestorOnboardingOffer;
+  }
+
+  setTransactionType(): void {
+    this.transaction.transactionType = TransactionType.EndInvestorOnboardingOffer;
+  }
+
+  setTransaction(_transaction: CantonPrepareCommandResponse): void {
+    throw new Error('Not implemented!');
+  }
+
+  /** @inheritDoc */
+  addSignature(_publicKey: PublicKey, _signature: Buffer): void {
+    throw new Error('Not implemented!');
+  }
+
+  /**
+   * Sets the on-chain contractId of the EndInvestorOnboardingOffer.
+   * Also sets the transaction id.
+   * @param id - contract id (from pendingContractId)
+   */
+  contractId(id: string): this {
+    if (!id || !id.trim()) {
+      throw new Error('contractId must be a non-empty string');
+    }
+    this._contractId = id.trim();
+    this.transaction.id = id.trim();
+    return this;
+  }
+
+  /**
+   * Sets the Canton party ID of the end investor being onboarded.
+   * @param id - end investor party id
+   */
+  endInvestorPartyId(id: string): this {
+    if (!id || !id.trim()) {
+      throw new Error('endInvestorPartyId must be a non-empty string');
+    }
+    this._endInvestorPartyId = id.trim();
+    return this;
+  }
+
+  /**
+   * Sets the Canton party ID of the participant that created the offer.
+   * @param id - participant party id (may be external to BitGo)
+   */
+  participantPartyId(id: string): this {
+    if (!id || !id.trim()) {
+      throw new Error('participantPartyId must be a non-empty string');
+    }
+    this._participantPartyId = id.trim();
+    return this;
+  }
+
+  /**
+   * Sets an optional free-form comment from the participant.
+   * @param comment - comment string
+   */
+  comment(comment: string): this {
+    this._comment = comment;
+    return this;
+  }
+
+  /**
+   * Builds and returns the EndInvestorOnboardingOfferData object from the builder's internal state.
+   *
+   * @returns {EndInvestorOnboardingOfferData} - A fully constructed and validated data object.
+   * @throws {Error} If any required field is missing.
+   */
+  toRequestObject(): EndInvestorOnboardingOfferData {
+    this.validate();
+    const result: EndInvestorOnboardingOfferData = {
+      contractId: this._contractId,
+      endInvestorPartyId: this._endInvestorPartyId,
+      participantPartyId: this._participantPartyId,
+    };
+    if (this._comment !== undefined) {
+      result.comment = this._comment;
+    }
+    return result;
+  }
+
+  protected async buildImplementation(): Promise<Transaction> {
+    this.validate();
+    this.transaction.endInvestorOnboardingOfferData = this.toRequestObject();
+    return this.transaction;
+  }
+
+  private validate(): void {
+    if (!this._contractId) throw new Error('contractId is missing');
+    if (!this._endInvestorPartyId) throw new Error('endInvestorPartyId is missing');
+    if (!this._participantPartyId) throw new Error('participantPartyId is missing');
+  }
+}
diff --git a/modules/sdk-coin-canton/src/lib/iface.ts b/modules/sdk-coin-canton/src/lib/iface.ts
index ee1871bfbb..6df9b6b393 100644
--- a/modules/sdk-coin-canton/src/lib/iface.ts
+++ b/modules/sdk-coin-canton/src/lib/iface.ts
@@ -34,6 +34,7 @@ export interface TxData {
   acknowledgeData?: TransferAcknowledge;
   cosignDelegationProposalData?: CosignDelegationProposal;
   allocationRequestData?: AllocationRequest;
+  endInvestorOnboardingOfferData?: EndInvestorOnboardingOfferData;
   memoId?: string;
   token?: string;
   cantonCommand?: CantonCommandExplain;
@@ -128,6 +129,7 @@ export interface TransactionBroadcastData {
   acknowledgeData?: TransferAcknowledge;
   cosignDelegationProposalData?: CosignDelegationProposal;
   allocationRequestData?: AllocationRequest;
+  endInvestorOnboardingOfferData?: EndInvestorOnboardingOfferData;
   prepareCommandResponse?: CantonPrepareCommandResponse;
   txType: string;
   preparedTransaction?: string;
@@ -226,6 +228,23 @@ export interface AllocationRequest {
   comment?: string;
 }
 
+/**
+ * Internal (non-signable) data for an EndInvestorOnboardingOffer txRequest.
+ * Records an on-chain EndInvestorOnboardingOffer contract on the end investor's wallet
+ * so they can accept or reject. Built locally without an IMS call — the participant
+ * party may be external (non-BitGo) and therefore not registered in BitGo's IMS.
+ */
+export interface EndInvestorOnboardingOfferData {
+  /** The on-chain contractId of the EndInvestorOnboardingOffer (from pendingContractId). */
+  contractId: string;
+  /** Canton party ID of the end investor being onboarded. */
+  endInvestorPartyId: string;
+  /** Canton party ID of the participant that created the offer (may be external to BitGo). */
+  participantPartyId: string;
+  /** Optional comment from the participant. */
+  comment?: string;
+}
+
 export const CANTON_COMMAND_KEYS = ['CreateCommand', 'ExerciseCommand'] as const;
 export type CantonCommandKind = (typeof CANTON_COMMAND_KEYS)[number];
 
diff --git a/modules/sdk-coin-canton/src/lib/index.ts b/modules/sdk-coin-canton/src/lib/index.ts
index bc5994865d..b824b600e4 100644
--- a/modules/sdk-coin-canton/src/lib/index.ts
+++ b/modules/sdk-coin-canton/src/lib/index.ts
@@ -6,6 +6,7 @@ export { AllocationAllocateBuilder } from './allocationAllocateBuilder';
 export { AllocationAllocateWithdrawnBuilder } from './allocationAllocateWithdrawnBuilder';
 export { AllocationRejectBuilder } from './allocationRejectBuilder';
 export { AllocationRequestBuilder } from './allocationRequestBuilder';
+export { EndInvestorOnboardingOfferBuilder } from './endInvestorOnboardingOfferBuilder';
 export { CosignDelegationAcceptBuilder } from './cosignDelegationAcceptBuilder';
 export { CosignDelegationProposalBuilder } from './cosignDelegationProposalBuilder';
 export { KeyPair } from './keyPair';
diff --git a/modules/sdk-coin-canton/src/lib/transaction/transaction.ts b/modules/sdk-coin-canton/src/lib/transaction/transaction.ts
index 0a188deb16..cbf9cf2955 100644
--- a/modules/sdk-coin-canton/src/lib/transaction/transaction.ts
+++ b/modules/sdk-coin-canton/src/lib/transaction/transaction.ts
@@ -12,6 +12,7 @@ import {
   CantonCommandExplain,
   CantonPrepareCommandResponse,
   CosignDelegationProposal,
+  EndInvestorOnboardingOfferData,
   MultiHashSignature,
   PartySignature,
   PreparedTxnParsedInfo,
@@ -29,6 +30,7 @@ export class Transaction extends BaseTransaction {
   private _acknowledgeData: TransferAcknowledge;
   private _cosignDelegationProposalData: CosignDelegationProposal;
   private _allocationRequestData: AllocationRequest;
+  private _endInvestorOnboardingOfferData: EndInvestorOnboardingOfferData;
   private _cantonCommandActAs: string[];
 
   constructor(coinConfig: Readonly<CoinConfig>) {
@@ -59,6 +61,10 @@ export class Transaction extends BaseTransaction {
     this._allocationRequestData = data;
   }
 
+  set endInvestorOnboardingOfferData(data: EndInvestorOnboardingOfferData) {
+    this._endInvestorOnboardingOfferData = data;
+  }
+
   set cantonCommandActAs(parties: string[]) {
     this._cantonCommandActAs = parties;
   }
@@ -123,6 +129,17 @@ export class Transaction extends BaseTransaction {
       };
       return Buffer.from(JSON.stringify(minData)).toString('base64');
     }
+    if (this._type === TransactionType.EndInvestorOnboardingOffer) {
+      if (!this._endInvestorOnboardingOfferData) {
+        throw new InvalidTransactionError('EndInvestorOnboardingOfferData is not set');
+      }
+      const minData: TransactionBroadcastData = {
+        txType: TransactionType[this._type],
+        submissionId: this.id,
+        endInvestorOnboardingOfferData: this._endInvestorOnboardingOfferData,
+      };
+      return Buffer.from(JSON.stringify(minData)).toString('base64');
+    }
     if (!this._prepareCommand) {
       throw new InvalidTransactionError('Empty transaction data');
     }
@@ -206,6 +223,13 @@ export class Transaction extends BaseTransaction {
       result.allocationRequestData = this._allocationRequestData;
       return result;
     }
+    if (this._type === TransactionType.EndInvestorOnboardingOffer) {
+      if (!this._endInvestorOnboardingOfferData) {
+        throw new InvalidTransactionError('EndInvestorOnboardingOfferData is not set');
+      }
+      result.endInvestorOnboardingOfferData = this._endInvestorOnboardingOfferData;
+      return result;
+    }
     if (this._type === TransactionType.CantonCommand) {
       if (!this._prepareCommand?.preparedTransaction) {
         throw new InvalidTransactionError('Empty transaction data');
@@ -242,7 +266,8 @@ export class Transaction extends BaseTransaction {
     if (
       this._type === TransactionType.TransferAcknowledge ||
       this._type === TransactionType.CosignDelegationProposal ||
-      this._type === TransactionType.AllocationRequest
+      this._type === TransactionType.AllocationRequest ||
+      this._type === TransactionType.EndInvestorOnboardingOffer
     ) {
       return Buffer.from(DUMMY_HASH, 'base64');
     }
@@ -273,6 +298,10 @@ export class Transaction extends BaseTransaction {
         if (decoded.allocationRequestData) {
           this.allocationRequestData = decoded.allocationRequestData;
         }
+      } else if (this.type === TransactionType.EndInvestorOnboardingOffer) {
+        if (decoded.endInvestorOnboardingOfferData) {
+          this.endInvestorOnboardingOfferData = decoded.endInvestorOnboardingOfferData;
+        }
       } else {
         if (decoded.prepareCommandResponse) {
           this.prepareCommand = decoded.prepareCommandResponse;
@@ -398,6 +427,21 @@ export class Transaction extends BaseTransaction {
         }
         return explanation;
       }
+      case TransactionType.EndInvestorOnboardingOffer: {
+        // Non-signable notification record — no inputs, outputs, or amounts to explain.
+        return {
+          id: this.id,
+          displayOrder,
+          outputs: [],
+          outputAmount: '0',
+          inputs: [],
+          inputAmount: '0',
+          changeOutputs: [],
+          changeAmount: '0',
+          fee: { fee: '0' },
+          type: this.type,
+        };
+      }
     }
     return {
       id: this.id,
diff --git a/modules/sdk-coin-canton/src/lib/transactionBuilderFactory.ts b/modules/sdk-coin-canton/src/lib/transactionBuilderFactory.ts
index 6dc2eb4b8d..5568d04611 100644
--- a/modules/sdk-coin-canton/src/lib/transactionBuilderFactory.ts
+++ b/modules/sdk-coin-canton/src/lib/transactionBuilderFactory.ts
@@ -10,6 +10,7 @@ import { AllocationAllocateWithdrawnBuilder } from './allocationAllocateWithdraw
 import { AllocationRejectBuilder } from './allocationRejectBuilder';
 import { AllocationRequestBuilder } from './allocationRequestBuilder';
 import { CantonCommandBuilder } from './cantonCommandBuilder';
+import { EndInvestorOnboardingOfferBuilder } from './endInvestorOnboardingOfferBuilder';
 import { CosignDelegationAcceptBuilder } from './cosignDelegationAcceptBuilder';
 import { CosignDelegationProposalBuilder } from './cosignDelegationProposalBuilder';
 import { OneStepPreApprovalBuilder } from './oneStepPreApprovalBuilder';
@@ -76,6 +77,9 @@ export class TransactionBuilderFactory extends BaseTransactionBuilderFactory {
         case TransactionType.CantonCommand: {
           return this.getCantonCommandBuilder(tx);
         }
+        case TransactionType.EndInvestorOnboardingOffer: {
+          return this.getEndInvestorOnboardingOfferBuilder(tx);
+        }
         default: {
           throw new InvalidTransactionError('unsupported transaction');
         }
@@ -103,6 +107,10 @@ export class TransactionBuilderFactory extends BaseTransactionBuilderFactory {
     return TransactionBuilderFactory.initializeBuilder(tx, new CantonCommandBuilder(this._coinConfig));
   }
 
+  getEndInvestorOnboardingOfferBuilder(tx?: Transaction): EndInvestorOnboardingOfferBuilder {
+    return TransactionBuilderFactory.initializeBuilder(tx, new EndInvestorOnboardingOfferBuilder(this._coinConfig));
+  }
+
   getOneStepPreapprovalBuilder(tx?: Transaction): OneStepPreApprovalBuilder {
     return TransactionBuilderFactory.initializeBuilder(tx, new OneStepPreApprovalBuilder(this._coinConfig));
   }
diff --git a/modules/sdk-coin-canton/test/unit/builder/endInvestorOnboardingOffer/endInvestorOnboardingOfferBuilder.ts b/modules/sdk-coin-canton/test/unit/builder/endInvestorOnboardingOffer/endInvestorOnboardingOfferBuilder.ts
new file mode 100644
index 0000000000..cfd95d85db
--- /dev/null
+++ b/modules/sdk-coin-canton/test/unit/builder/endInvestorOnboardingOffer/endInvestorOnboardingOfferBuilder.ts
@@ -0,0 +1,133 @@
+import assert from 'assert';
+import should from 'should';
+
+import { coins } from '@bitgo/statics';
+
+import { EndInvestorOnboardingOfferBuilder, Transaction } from '../../../../src';
+import { EndInvestorOnboardingOfferData } from '../../../../src/lib/iface';
+
+const contractId =
+  '0020108b7aee0e0215538668a7ebb00e7e811135ff2ebf23137760056e077b9347ca121220dfa25cd905caba01345b515d1002af94b0ba2a9c2e9a6751c07ed28795454a9e';
+const endInvestorPartyId = 'end-investor-1::1220460fe6779731682d05fb151822f20f4a756f1d6fe84f38b8d91172947adbae24';
+const participantPartyId = 'bd::1220460fe6779731682d05fb151822f20f4a756f1d6fe84f38b8d91172947adbae24';
+const comment = 'welcome to DTCC onboarding';
+
+// Helper to set all required fields on a builder
+function buildWithAllRequired(txBuilder: EndInvestorOnboardingOfferBuilder): EndInvestorOnboardingOfferBuilder {
+  return txBuilder.contractId(contractId).endInvestorPartyId(endInvestorPartyId).participantPartyId(participantPartyId);
+}
+
+describe('EndInvestorOnboardingOffer Builder', () => {
+  it('should build the request object with all required fields', function () {
+    const txBuilder = new EndInvestorOnboardingOfferBuilder(coins.get('tcanton'));
+    const tx = new Transaction(coins.get('tcanton'));
+    txBuilder.initBuilder(tx);
+    buildWithAllRequired(txBuilder).comment(comment);
+    const requestObj: EndInvestorOnboardingOfferData = txBuilder.toRequestObject();
+    should.exist(requestObj);
+    assert.equal(requestObj.contractId, contractId);
+    assert.equal(requestObj.endInvestorPartyId, endInvestorPartyId);
+    assert.equal(requestObj.participantPartyId, participantPartyId);
+    assert.equal(requestObj.comment, comment);
+  });
+
+  it('should build the request object without optional comment', function () {
+    const txBuilder = new EndInvestorOnboardingOfferBuilder(coins.get('tcanton'));
+    const tx = new Transaction(coins.get('tcanton'));
+    txBuilder.initBuilder(tx);
+    buildWithAllRequired(txBuilder);
+    const requestObj: EndInvestorOnboardingOfferData = txBuilder.toRequestObject();
+    should.exist(requestObj);
+    assert.equal(requestObj.comment, undefined);
+  });
+
+  it('should set the transaction id to the contractId', function () {
+    const txBuilder = new EndInvestorOnboardingOfferBuilder(coins.get('tcanton'));
+    const tx = new Transaction(coins.get('tcanton'));
+    txBuilder.initBuilder(tx);
+    txBuilder.contractId(contractId);
+    assert.equal(tx.id, contractId);
+  });
+
+  it('should produce a round-trippable serialized transaction', function () {
+    const txBuilder = new EndInvestorOnboardingOfferBuilder(coins.get('tcanton'));
+    const tx = new Transaction(coins.get('tcanton'));
+    txBuilder.initBuilder(tx);
+    buildWithAllRequired(txBuilder).comment(comment);
+    const requestObj = txBuilder.toRequestObject();
+    tx.endInvestorOnboardingOfferData = requestObj;
+
+    const serialized = tx.toBroadcastFormat();
+    const tx2 = new Transaction(coins.get('tcanton'));
+    tx2.fromRawTransaction(serialized);
+    const tx2Json = tx2.toJson();
+    should.exist(tx2Json.endInvestorOnboardingOfferData);
+    assert.equal(tx2Json.endInvestorOnboardingOfferData!.contractId, contractId);
+    assert.equal(tx2Json.endInvestorOnboardingOfferData!.endInvestorPartyId, endInvestorPartyId);
+    assert.equal(tx2Json.endInvestorOnboardingOfferData!.participantPartyId, participantPartyId);
+    assert.equal(tx2Json.endInvestorOnboardingOfferData!.comment, comment);
+  });
+
+  it('should return DUMMY_HASH as the signable payload', function () {
+    const txBuilder = new EndInvestorOnboardingOfferBuilder(coins.get('tcanton'));
+    const tx = new Transaction(coins.get('tcanton'));
+    txBuilder.initBuilder(tx);
+    buildWithAllRequired(txBuilder);
+    const requestObj = txBuilder.toRequestObject();
+    tx.endInvestorOnboardingOfferData = requestObj;
+    // signablePayload must be non-empty (it returns the DUMMY_HASH buffer)
+    assert.ok(tx.signablePayload.length > 0);
+  });
+
+  // --- missing required field tests ---
+
+  it('should throw if contractId is missing', function () {
+    const txBuilder = new EndInvestorOnboardingOfferBuilder(coins.get('tcanton'));
+    txBuilder.initBuilder(new Transaction(coins.get('tcanton')));
+    txBuilder.endInvestorPartyId(endInvestorPartyId).participantPartyId(participantPartyId);
+    assert.throws(() => txBuilder.toRequestObject(), /contractId is missing/);
+  });
+
+  it('should throw if endInvestorPartyId is missing', function () {
+    const txBuilder = new EndInvestorOnboardingOfferBuilder(coins.get('tcanton'));
+    txBuilder.initBuilder(new Transaction(coins.get('tcanton')));
+    txBuilder.contractId(contractId).participantPartyId(participantPartyId);
+    assert.throws(() => txBuilder.toRequestObject(), /endInvestorPartyId is missing/);
+  });
+
+  it('should throw if participantPartyId is missing', function () {
+    const txBuilder = new EndInvestorOnboardingOfferBuilder(coins.get('tcanton'));
+    txBuilder.initBuilder(new Transaction(coins.get('tcanton')));
+    txBuilder.contractId(contractId).endInvestorPartyId(endInvestorPartyId);
+    assert.throws(() => txBuilder.toRequestObject(), /participantPartyId is missing/);
+  });
+
+  // --- invalid setter argument tests ---
+
+  it('should throw if contractId is an empty string', function () {
+    const txBuilder = new EndInvestorOnboardingOfferBuilder(coins.get('tcanton'));
+    assert.throws(() => txBuilder.contractId(''), /contractId must be a non-empty string/);
+  });
+
+  it('should throw if endInvestorPartyId is an empty string', function () {
+    const txBuilder = new EndInvestorOnboardingOfferBuilder(coins.get('tcanton'));
+    assert.throws(() => txBuilder.endInvestorPartyId(''), /endInvestorPartyId must be a non-empty string/);
+  });
+
+  it('should throw if participantPartyId is an empty string', function () {
+    const txBuilder = new EndInvestorOnboardingOfferBuilder(coins.get('tcanton'));
+    assert.throws(() => txBuilder.participantPartyId(''), /participantPartyId must be a non-empty string/);
+  });
+
+  // --- not-implemented methods ---
+
+  it('should throw on setTransaction', function () {
+    const txBuilder = new EndInvestorOnboardingOfferBuilder(coins.get('tcanton'));
+    assert.throws(() => txBuilder.setTransaction({} as any), /Not implemented/);
+  });
+
+  it('should throw on addSignature', function () {
+    const txBuilder = new EndInvestorOnboardingOfferBuilder(coins.get('tcanton'));
+    assert.throws(() => txBuilder.addSignature({} as any, Buffer.from('')), /Not implemented/);
+  });
+});
diff --git a/modules/sdk-core/src/account-lib/baseCoin/enum.ts b/modules/sdk-core/src/account-lib/baseCoin/enum.ts
index 811945cae3..02777ac187 100644
--- a/modules/sdk-core/src/account-lib/baseCoin/enum.ts
+++ b/modules/sdk-core/src/account-lib/baseCoin/enum.ts
@@ -111,6 +111,10 @@ export enum TransactionType {
   AllocationReject,
   // canton generic DAML command
   CantonCommand,
+  // canton end investor onboarding offer (internal/dummy txRequest recording an on-chain
+  // EndInvestorOnboardingOffer contract on the end investor's wallet so they can accept or reject.
+  // Never signed or submitted — built locally without an IMS call.)
+  EndInvestorOnboardingOffer,
 
   // trx
   FREEZE,