Choose Mercury if you want an online business bank account first, with free checking and savings, invoicing, bill payments and now payroll in one app. Choose Brex if spend control is the priority: corporate cards, AI expense management, travel and bill pay, with multi-entity support as you expand internationally. Read the small print on deposits, because Mercury says it's a fintech company, not an FDIC-insured bank, with banking services provided through Choice Financial Group and Column N.A., Members FDIC.
Both are popular with US startups, and both have widened their products a lot, so I read Mercury's home, about and plans pages and Brex's home, plans, business account and about pages to see where each one really starts.
Mercury and Brex compared
| Mercury | Brex | |
|---|---|---|
| Starting point | Online business banking | Corporate cards and spend management |
| Bank account | Free checking and savings accounts, zero minimums | Business account with checking and treasury |
| Cards and expenses | Cards, reimbursements, limits and approvals | Global cards with AI-powered rules and expense automation |
| Bills and invoices | Bill pay and free invoices | AI-powered invoice entry and bill pay |
| Payroll | Mercury Payroll | Not mentioned on the pages I read |
| International | Payments around the world | Local cards in 50+ countries, multi-entity on Premium |
| Free option (as of October 2026) | Free checking and savings accounts | Essentials plan with no per-user charge |
Who holds your money
This is the detail to check before you move a company's cash. Mercury's about page says plainly that Mercury is a fintech company, not an FDIC-insured bank, and that banking services are provided through Choice Financial Group and Column N.A., Members FDIC. Brex's business account page highlights FDIC coverage and a treasury account invested mainly in US government-backed securities. Neither page should replace your own reading of the account terms, but it's worth knowing that both are software companies working with partners.
What Mercury includes
Mercury pitches radically different banking: you apply online in about ten minutes and run the account from its app. Its home page lists free checking and savings accounts with zero minimums, Treasury by Mercury Advisory, loans, credit cards with team controls, payments and invoicing, and accounting sync with QuickBooks, Xero and NetSuite. It has also added Mercury Payroll for full-service payroll and an AI-powered accounting product called Books. Mercury says it's used by 450K+ entrepreneurs, and its customer stories range from software companies to ecommerce brands and agencies, which tells you it's aimed at small and growing firms rather than large corporates.
More company cards are listed in our corporate card roundup.
What Brex includes
Brex calls itself a finance software platform and says the card is just the start. It offers corporate cards with built-in controls, AI that automates approvals and expense reports, in-app travel booking, bill pay and banking and treasury. Its plans start with Essentials for startups and growing companies, which includes global card acceptance, one local card program, up to two entities, accounting integrations, bill pay, reimbursements and travel booking. Premium adds multi-entity support across the US and other countries, ERP and HRIS integrations and VAT documentation, and Enterprise covers unlimited entities. Brex says it's trusted by 35,000+ companies and offers separate routes for startups, mid-size companies and enterprises, so it's clearly built to grow with a business rather than stay small.
Another business bank is reviewed in our Relay review.
Which fits your company
- Need a business bank account above all? Mercury was built for that.
- Spending across many employees and want tight controls? Brex's cards and AI rules focus there.
- Running payroll and invoices from the same app as your bank? Mercury now does both.
- Operating entities in several countries? Brex Premium and Enterprise cover multi-entity setups.
- Want to start without a monthly commitment? Both have free starting points.
Whatever you choose, keep your personal and business finances separate, and read up on the benefits of a credit card for your small business before you hand cards to the team.
My advice on Mercury or Brex
For a young company that mainly needs somewhere to hold cash, pay bills and invoice clients, I'd start with Mercury's free accounts. Once spending spreads across many employees, countries or entities, Brex's spend controls start to earn their place, and nothing stops you using a bank account from one and cards from the other. Whatever you do, read each provider's account terms on deposit coverage yourself, because that's your company's money.
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Do you make finance tools? Tool makers can ask to be considered for a featured place in comparisons like this one.
Related: loans: guidelines and how to pitch.
Frequently asked questions
Is Mercury a bank?
No. Mercury says it's a fintech company, not an FDIC-insured bank, with banking services provided through Choice Financial Group and Column N.A., Members FDIC.
Does Mercury have free accounts?
Yes. Mercury's home page lists free checking and savings accounts with zero minimums.
Is Brex free?
Brex's Essentials plan has no per-user charge and includes global card acceptance, bill pay, reimbursements and travel booking. Premium and Enterprise are paid plans.
Does Mercury offer payroll?
Yes. Mercury has introduced Mercury Payroll, which it describes as AI-powered, full-service payroll.
Can Brex handle several entities?
Yes. Essentials covers up to two entities, Premium adds multi-entity support across the US and other countries, and Enterprise allows unlimited entities.
