Restrict Eligible Holders

Keep tokenized shares within an approved set of holders by binding a B20 allowlist to issuance and transfers.

Create an allowlist in the Policy Registry, then apply it when shares are issued, sent, or received. Accounts remain ineligible until the policy admin adds them.

Demo

Complete Launch a B20 token first. These samples target base-std@v1.0.0, viem@2.55.11, and Base Foundry v1.1.1.

Create and bind the eligibility policy

TypeScript

import { parseEventLogs, type Address } from "viem";
import { account } from "../../shared/clients.js";
import { POLICY_REGISTRY, b20Abi, policyRegistryAbi, scope } from "../abi.js";
import { sendContract } from "../write.js";

export async function restrictStockHolders(token: Address, holders: Address[]) {
  const receipt = await sendContract({ address: POLICY_REGISTRY, abi: policyRegistryAbi, functionName: "createPolicyWithAccounts", args: [account.address, 1, holders] });
  const [created] = parseEventLogs({ abi: policyRegistryAbi, logs: receipt.logs, eventName: "PolicyCreated" });
  for (const policyScope of [scope("MINT_RECEIVER_POLICY"), scope("TRANSFER_SENDER_POLICY"), scope("TRANSFER_RECEIVER_POLICY")]) {
    await sendContract({ address: token, abi: b20Abi, functionName: "updatePolicy", args: [policyScope, created.args.policyId] });
  }
  return created.args.policyId;
}

See the complete verified B20 examples for imports, client construction, and runnable projects.

The same allowlist policy gates mint recipients, transfer senders, and transfer recipients.

Seed all intended holders before binding an allowlist. An unlisted account becomes ineligible immediately.

See also

• Cancel blocked shares · Pause transfers
• Policy Registry and Policy integration in the B20 standard