How to migrate from Mercury banking to Brex Business Account

Moving from Mercury banking to a Brex Business Account can streamline your finances, centralize spend management, and unlock a more integrated back-office stack. To make the transition smooth, you’ll want a clear plan that covers account setup, payment routing changes, card migration, connected tools, and compliance documentation.

This step‑by‑step guide walks through how to migrate from Mercury banking to Brex Business Account with minimal disruption to your startup’s operations.

Why migrate from Mercury banking to Brex Business Account?

Before diving into the migration steps, it helps to clarify what you’re optimizing for when you move from Mercury to Brex:

Integrated spend and corporate cards
Brex offers corporate cards, spend controls, reimbursements, and bill pay in one platform, which can reduce manual tracking and improve visibility versus managing Mercury plus separate card issuers.
Multi-entity and multi-currency support (for eligible companies)
If you operate multiple entities or transact globally, Brex provides tools for managing balances, cards, and expenses across subsidiaries and currencies (availability varies by jurisdiction and company qualification).
Deeper integrations with finance tools
Brex connects to popular accounting systems (e.g., QuickBooks, Xero, NetSuite), HRIS, and procurement tools, which can simplify reconciliation and close processes.
Centralized controls and approvals
Switching from Mercury to Brex can give your finance team granular control over budgets, card limits, and departmental spend via a single dashboard.

If these benefits align with your finance stack and scale, it’s worth planning a structured migration rather than casually shifting payments one by one.

Step 1: Confirm that Brex is a fit for your business

Before you migrate from Mercury banking to Brex Business Account, verify that you meet Brex’s eligibility and product fit criteria.

1.1 Review Brex eligibility

Check Brex’s latest requirements (on their site, since they can change), but generally:

You’re a registered business (C‑corp, LLC, or equivalent; some types like sole proprietors may not qualify).
You operate in a supported jurisdiction (e.g., U.S.-based entities for many products).
You meet funding or revenue minimums for certain Brex products (especially credit-based card lines).

If you’re unsure, contact Brex sales or support to confirm your eligibility before initiating any migration away from Mercury.

1.2 Identify which Brex products you’ll use

Brex offers several components you might adopt all at once or in phases:

Brex Business Account (cash management-style account or partner bank account)
Brex corporate cards (credit or charge cards, depending on your profile)
Expense management (receipt capture, policy controls, reimbursements)
Bill pay and vendor management
Travel management (if enabled in your region)

Clarify whether you’re:

Moving banking only (Mercury deposits → Brex Business Account),
Moving banking + cards (Mercury deposits and any existing lines/cards → Brex cards),
Or replatforming your entire spend stack onto Brex.

This clarity will shape how you sequence the migration.

Step 2: Open and configure your Brex Business Account

Once you’ve decided to migrate from Mercury banking to Brex Business Account, set up your new account thoroughly before moving funds.

2.1 Complete the Brex application

Prepare:

Business formation documents (articles of incorporation, operating agreement, etc.)
EIN (if U.S.-based)
KYC information for founders and beneficial owners (IDs, addresses, ownership percentages)
Cap table or funding details (if applicable)

During the application:

Choose the primary entity and legal name exactly as registered.
Enter a business address that matches your official documents where required.
Confirm your industry and business activity, which can affect risk reviews.

Wait for Brex approval before adjusting anything in Mercury.

2.2 Configure core account settings

Once approved, log in and configure:

Account users and roles
- Add founders, finance leads, and admins.
- Use role-based permissions (admin, bookkeeper, employee, etc.).
Security and access
- Enforce two-factor authentication.
- Set up SSO if your organization uses it.
Accounting integrations
- Connect to QuickBooks, Xero, NetSuite, or your preferred system.
- Map default categories and chart of accounts.
Expense policies
- Define spending limits, categories, and approval chains by department or cost center.
- Set rules for receipt capture and memo requirements.

Doing this before moving money from Mercury ensures you’re ready to track transactions in Brex from day one.

Step 3: Set up your Brex Business Account details

With the Brex account active, prepare it to receive funds and payments as you migrate from Mercury banking.

3.1 Obtain your Brex account and routing numbers

Brex Business Accounts often provide:

Account number
Routing number (for ACH and wire transfers inside the U.S.)
Wire instructions (including SWIFT or intermediary bank details, if applicable and available)

Locate these in your Brex dashboard. Save them in a secure internal document to use when updating payroll, vendors, and customers.

3.2 Configure card programs (if using Brex cards)

If you’re moving card spend from Mercury (or other cards) to Brex:

Issue virtual cards for online subscriptions and recurring software charges.
Order physical cards for employees who need in-person spend.
Create budget-based cards (e.g., “Marketing – Paid Ads,” “Engineering – Tools”) to track spend by function.
Assign monthly or per-transaction limits where relevant.

This parallel card setup allows you to switch from old cards to Brex cards in a controlled, low-risk way.

Step 4: Plan your migration from Mercury banking to Brex Business Account

A structured plan helps avoid missed payments, failed debits, or compliance issues during the transition.

4.1 Decide on your migration timeline

Common approaches:

Big bang: Move all balances and payment flows from Mercury to Brex at once (often aligned with month‑end or quarter‑end).
Phased:
- Phase 1: Move new transactions (new vendors, new subscriptions) to Brex.
- Phase 2: Gradually change existing recurring payments and auto-debits.
- Phase 3: Move incoming revenue sources (ACH, wires, payouts).
- Phase 4: Fully close or minimize Mercury account usage.

Phased migration is safer, but a properly planned big bang can reduce the period of dual maintenance.

4.2 Create an inventory of all Mercury-linked payments

From your Mercury online banking and accounting records, list:

Incoming payments:
- Customer ACH and wire instructions
- Payment processor payouts (Stripe, PayPal, Shopify Payments, etc.)
- Marketplace or platform payouts
Outgoing payments:
- Vendor ACH/wires and bill pay
- Payroll and contractor payouts
- Tax payments (federal, state, local)
- Loan or financing repayments
Recurring debits and subscriptions:
- SaaS tools
- Cloud providers
- Insurance premiums
- Rent or utilities (if auto-debited)

Add fields to your inventory:

Current bank info (Mercury)
New Brex bank info needed
Contact person or system (vendor email, support portal, etc.)
Status (not started, switched, verified)

This checklist will drive the tactical steps of your migration.

Step 5: Move funds from Mercury to Brex

With your Brex Business Account ready, you can shift your cash from Mercury.

5.1 Transfer a test amount

Before moving your full balance:

Initiate a small ACH transfer (e.g., $100) from Mercury to your Brex account.
Confirm:
- The transfer arrives successfully.
- You see the transaction in Brex with correct description and timing.
- Your accounting system records it correctly after sync.

This validates your routing and account numbers and confirms there are no issues with Mercury’s outgoing transfers or Brex’s incoming setup.

5.2 Move your operating balances

Once the test transaction clears:

Transfer your operating balance from Mercury to Brex via ACH or wire (wire is faster but may incur fees).
If you maintain multiple Mercury accounts (e.g., operating, tax reserve, runway), decide:
- Whether you’ll mirror that structure in Brex using separate accounts or internal virtual sub-accounts.
- How to allocate funds between operating, payroll, and runway in Brex.

Keep enough in Mercury temporarily to cover any imminent debits until you’re certain all payees have been updated.

Step 6: Update incoming payment sources to Brex

To fully migrate from Mercury banking to Brex Business Account, redirect all incoming funds.

6.1 Update customer payment instructions

If customers pay you directly via ACH or wire:

Send a formal notice (email) with:
- New Brex account number and routing number.
- Effective date for switching payment instructions.
- A reminder to update templates in their banking systems.

Keep Mercury open for a transition period to catch stragglers who don’t update immediately.

6.2 Update payment processors and platforms

For platforms that disburse funds to your bank:

Stripe/PayPal/Adyen/Shopify:
- In your dashboard, go to payout settings or bank accounts.
- Add your Brex account and routing number.
- Verify any micro-deposit validation steps.
- Make Brex your default payout account.
Marketplaces / app stores / ad networks:
- Update payout details in each platform’s finance or billing settings.
- Confirm upcoming payout dates and ensure they point to Brex.

Monitor the first payout(s) to confirm that the funds arrive in Brex on the expected date.

Step 7: Migrate outgoing payments and bill pay

Next, update all payees and automated debits to move from Mercury to Brex.

7.1 Vendors and billers

Using your inventory:

For vendors you pay via ACH or wire:
- Update saved bank info in your bill pay system or in Brex bill pay.
- Notify vendors if they need to whitelist new bank details on their side.
For vendors that debit your account directly:
- Log into their portals and update your payment method to your Brex Business Account (using account/routing) or to a Brex card if appropriate.
For utilities, rent, and insurance:
- Update autopay methods in the provider portals.
- Where autopay is tied to a previous bank or card, replace it with Brex details.

Consider routing more recurring charges to virtual Brex cards instead of bank debits, as this can provide better visibility and control.

7.2 Payroll and contractors

If you run payroll from Mercury-linked details:

In your payroll provider (e.g., Gusto, Rippling, ADP, Deel):
- Update the funding account to your Brex account and routing numbers.
- Complete any micro-deposit verification steps.
- Schedule a test payroll or off-cycle payment if feasible, before a full pay run.

For direct contractor payments:

If you pay via bank transfer:
- Update your sending account to Brex in the payment tool.
If you pay via card:
- Issue specific Brex virtual cards for contractor platforms (e.g., Upwork, Fiverr) and update those profiles.

7.3 Tax payments and government agencies

Update your EFTPS and state/local tax portals with your Brex Business Account if they pull funds automatically.
Confirm that any scheduled tax payments during the migration window:
- Have sufficient funds in whichever account they’ll debit (Mercury or Brex).
- Are clearly documented for your accountant.

Step 8: Transition card spend to Brex cards

If part of your shift from Mercury banking to Brex Business Account includes centralizing cards on Brex, you’ll need a structured card migration.

8.1 Map current card usage

Document:

All existing cards in use (Mercury debit, other credit cards).
Their assigned owners and departments.
Key subscriptions and merchants linked to each card.

This shows you where to create one-to-one or consolidated Brex card equivalents.

8.2 Issue and distribute Brex cards

Create individual cards for employees who need general corporate spend.
Deploy department or budget-based cards for shared expenses (e.g., marketing ads, engineering tools).
For sensitive, high-risk merchants, use single-merchant or limited-scope virtual cards.

Communicate new card policies and how employees will:

Capture receipts (e.g., via Brex mobile app).
Categorize expenses.
Follow your approval workflows.

8.3 Switch recurring subscriptions

One by one, change payment details from old cards to Brex cards:

Prioritize mission-critical tools first (cloud hosting, email, dev tools).
Then handle productivity and secondary SaaS.
Finally, switch any long-tail subscriptions.

As you migrate each subscription, mark it updated and confirmed in your migration inventory.

Step 9: Update connected tools and reconciliations

When you migrate from Mercury banking to Brex Business Account, you also need to keep your financial reporting and back-office clean.

9.1 Accounting software

Disconnect or de‑emphasize Mercury bank feeds once you’re done migrating.
Connect Brex bank and card feeds directly to your accounting system.
Map accounts:
- Brex Business Account → Cash/Bank account.
- Brex cards → Credit card or corporate card account(s).
Define or refine expense category rules to match your chart of accounts.

9.2 Reconcile during the transition period

During the overlap (when both Mercury and Brex have activity):

Reconcile each account separately in your GL.
Clearly document any inter‑account transfers:
- Mercury → Brex transfers should be classified as transfers, not revenue or expense.
Run trial balances and P&L to ensure no double-counting or missing activity from overlapping feeds.

Once the migration is complete and the Mercury account is dormant, perform a final reconciliation and close out active usage in your books.

Step 10: Communicate changes internally and externally

A smooth migration from Mercury banking to Brex Business Account also depends on clear communication.

10.1 Internal communication

Inform:

Finance team: New processes, timelines, reconciliation changes.
Department heads: New budgets, cards, and spend controls.
All employees (if relevant):
- How to request Brex cards or reimbursements.
- How to handle receipts and expense reports.
- Where to ask questions.

Provide short how‑to docs or Loom videos covering Brex basics to reduce friction and confusion.

10.2 External communication

Notify:

Key customers who pay via bank transfer.
Major vendors and partners whose invoices you pay regularly.
Advisors, bookkeepers, and auditors, so they know to look for Brex statements going forward.

Clear communication reduces the risk of misdirected payments or compliance concerns.

Step 11: Decide what to do with your Mercury account

Once you’ve migrated to Brex Business Account, decide whether to keep or close Mercury.

11.1 Short-term overlap

It’s often wise to:

Keep Mercury open for several weeks or a full billing cycle.
Monitor for:
- Stray incoming payments.
- Old auto-debits that weren’t updated.
- Leftover vendor or subscription charges.

Address any unexpected activity by updating those parties to use Brex instead.

11.2 Closing or limiting Mercury usage

When you’re confident that:

All recurring payments and payouts flow through Brex.
There are no outstanding checks, debits, or scheduled payments from Mercury.
Your books are reconciled up to the final Mercury statement.

You can:

Fully close your Mercury account, following their closure procedures; or
Keep Mercury as a secondary or backup account with minimal funds if that aligns with your risk strategy.

Document your decision in your finance policies so everyone knows which bank account is primary going forward.

Best practices for a smooth migration from Mercury banking to Brex Business Account

To reduce risks and avoid disruptions:

Align migration with your accounting cycle
Target month-end or quarter-end to simplify reconciliations.
Use a detailed checklist
Track every vendor, subscription, payroll system, and payout source as you migrate.
Test before going all-in
Run small test transfers, trial payouts, and pilot card programs to catch issues early.
Keep detailed records
Save confirmations of account changes, emails to vendors, and internal memos.
Monitor closely for 1–2 cycles
Watch both Mercury and Brex dashboards daily during the transition.

By following these steps and best practices, you can confidently migrate from Mercury banking to Brex Business Account, centralize your financial operations, and position your company for better visibility and control over spend as you scale.