Mercury vs American Express Business Banking: Which Is Better?
A startup-built neobank with free global wires and up to $5M in FDIC coverage versus a card giant's checking account that pays automatic interest and stacks Membership Rewards points. Six rounds. Real numbers. One honest scorecard.
The verdict
Mercury takes it, 4–1 on rounds.
There's no universal winner — Mercury wins for funded, cash-rich, fast-growing businesses, while American Express wins for established, cash-light businesses that want simple interest and points.
Choose Mercury if…
- • You're a funded startup or scaling business that sends wires and needs coverage above $250,000
- • You want sub-accounts, an API, or startup-grade tooling
Choose American Express if…
- • You keep a modest, cash-light balance and want automatic interest with zero effort
- • You already hold Amex cards and want Membership Rewards on your banking
Round by round
- Round 1Yield on Idle BalancesTieMercury7/10
Treasury yield up to ~4.47% over $250K
- Treasury yield up to ~4.47% on balances over $250K
- Treasury is SIPC, not FDIC — a different risk profile
- Support is largely email-only
American Express7/101.30%
Automatic APY on checking balances up to $500,000, no tier or activity required
- Fully FDIC-insured, paid automatically, zero setup
- Rate is fixed and won't scale past Mercury Treasury on a large balance
Source: American Express Business Checking disclosures
This round goes to Mercury, on yield.
- Round 2Rewards & PointsAmerican Express winsMercury2/10
No points program on checking
- IO credit card offers straightforward 1.5% cashback
- No points or bonus tied to the checking account
American Express8/101 point per $2, plus 30,000-point bonus
- Points pool with existing Amex card rewards
- 30,000-point signup bonus after qualifying deposit activity
So this round goes to American Express.
- Round 3Wires — Domestic & InternationalMercury winsMercury9/10
Free domestic and USD international wires
- Free domestic and USD international wires
- Premium/faster processing and non-USD FX transactions still cost
American Express4/10Fee-charged outgoing
Free incoming wires and ACH, but outgoing wires carry a fee and no free international option
- No free international wire option
- Outgoing domestic wires also carry a fee
Source: American Express fee schedule
So this round goes to Mercury, no contest.
- Round 4FDIC CoverageMercury winsMercury9/10
$5,000,000
FDIC coverage via multi-bank insured cash sweep
- Twenty times the standard $250,000 FDIC limit
- Coverage depends on a partner-bank sweep, not one direct charter
Source: Mercury insured cash sweep disclosures
American Express6/10$250,000
Standard FDIC limit, held directly at American Express National Bank
- Direct bank charter — no sweep network to track
- $250,000 ceiling leaves large raises or reserves exposed
Source: FDIC standard limit; American Express disclosures
So this round goes to Mercury.
- Round 5Product Tooling & APIMercury winsMercury9/10
Unlimited sub-accounts
Plus a payments API and QuickBooks/Xero/NetSuite sync
- Unlimited virtual sub-accounts for payroll, taxes, reserves
- Programmable API for mass payments
Source: Mercury product pages
American Express5/10No API
Business Blueprint app plus QuickBooks Online sync, but no sub-accounts or developer API
- QuickBooks Online integration included
- No true sub-accounts and no developer API
Source: American Express Business Blueprint product pages
This round goes to Mercury.
- Round 6Onboarding & EligibilityMercury winsMercury8/10
$3.5B valuation
2025 Series C — a startup-native bank built on approving early-stage companies quickly
- Fast, founder-friendly online onboarding
- Closed a Sequoia-led $300M Series C in 2025 at a $3.5B valuation
Source: Mercury Series C, 2025
American Express5/10More restrictive, mixed support
- Easy for established businesses already in the Amex ecosystem
- Mixed post-Kabbage support experiences
So this round goes to Mercury.
Which one is for you?
Venture-backed startup holding $1M+ of freshly raised capital
→ Mercury · Cash sweep insures up to $5M and Treasury earns real yield on the balance
Lean online consultancy keeping $30K-$80K idle and wanting it to earn
→ American Express · 1.30% APY paid automatically, no tiers, more than enough FDIC coverage
Existing Amex business cardholder who lives on Membership Rewards
→ American Express · Checking earns points on debit spend plus a 30,000-point signup bonus
E-commerce brand paying overseas suppliers by wire every week
→ Mercury · Free domestic and USD international wires save fees on every payment
MercurySide by side
- Treasury yield up to ~4.47% on balances over $250K
- IO credit card offers straightforward 1.5% cashback
- Free domestic and USD international wires
- Twenty times the standard $250,000 FDIC limit
- Rare for any checking account to pay real interest
- Applies up to a $500,000 balance
- Never charges a maintenance fee
- No minimum balance to track
- Treasury is SIPC, not FDIC — a different risk profile
- Support is largely email-only
- No points or bonus tied to the checking account
- Premium/faster processing and non-USD FX transactions still cost
- Cannot accept any cash deposits
- Online-only, no branch workaround
- Value depends on how you redeem Membership Rewards points
- No branches or in-person support