Mercury vs Brex 2025: Best Banking for US Startups

Last Updated: December 2025 | Reading Time: 9 minutes

Mercury and Brex are the two most popular financial platforms for US startups. Both are designed specifically for tech companies, but they serve different needs. Mercury focuses on simple, free banking, while Brex offers corporate cards with rewards and expense management.

In this comprehensive comparison, we'll explore features, fees, credit cards, and help you determine which platform is the best fit for your startup.

Quick Comparison Table

Feature	Mercury	Brex
Best For	Early-stage startups, bootstrapped	Funded startups, high spend
Monthly Fee	$0	$0 (but requires spend)
FDIC Insurance	$5M (via partner banks)	$6M (via partner banks)
Domestic Wires	Free (unlimited)	Free (limited)
International Wires	$25 per wire	$15 per wire
ACH Transfers	Free (unlimited)	Free (unlimited)
Treasury Yield	4.5%+ APY	4.0%+ APY
Corporate Cards	Debit cards only	Credit cards (rewards)
Credit Limit	N/A (debit)	Based on cash + revenue
Rewards	None	1-7x points
Expense Management	Basic	Advanced
Accounting Integration	QuickBooks, Xero	QuickBooks, Xero, NetSuite
Approval Time	24-48 hours	1-3 business days

The Core Difference: Banking vs Corporate Cards

Mercury: Simple, Free Banking

Mercury's mission: Provide the best banking experience for startups.

Target customer:

• Early-stage startups (pre-seed, seed)
• Bootstrapped companies
• Startups prioritizing simplicity
• Companies that don't need credit

Value proposition: Free banking with excellent UX, no credit required.

Brex: Corporate Cards with Rewards

Brex's mission: Reimagine financial services for growing companies.

Target customer:

• Funded startups (seed, Series A+)
• High-spend companies ($50,000+/month)
• Companies wanting rewards on spend
• Businesses needing expense management

Value proposition: Corporate credit cards with rewards, no personal guarantee required.

Fee Structure: Detailed Breakdown

Banking Fees

Mercury:

• Monthly fee: $0
• Account opening: $0
• Domestic wires: Free (unlimited) 🎉
• International wires: $25 per wire
• ACH transfers: Free (unlimited)
• Check deposits: Free (mobile app)

Brex:

• Monthly fee: $0
• Account opening: $0
• Domestic wires: Free (up to 20/month, then $3 each)
• International wires: $15 per wire
• ACH transfers: Free (unlimited)
• Check deposits: Free (mobile app)

Verdict: Mercury wins on domestic wires (unlimited free vs 20 free). Brex wins on international wires ($15 vs $25).

Card Fees

Mercury:

• Debit cards: Free
• Virtual cards: Free
• Physical cards: Free
• Foreign transactions: 1% fee
• ATM withdrawals: 2% fee

Brex:

• Credit cards: Free
• Virtual cards: Free (unlimited)
• Physical cards: Free
• Foreign transactions: 2.7% fee
• No ATM access: Credit cards don't support ATM

Verdict: Mercury wins on foreign transactions (1% vs 2.7%). Brex offers credit (advantage for cash flow).

Treasury/Savings Yield

Mercury:

• Treasury yield: 4.5%+ APY (on US Treasury bills)
• Auto-invest: Set operating balance, invest excess
• Withdrawals: 1-2 business days
• FDIC insured: No (T-bills are government-backed)

Brex:

• Cash yield: 4.0%+ APY (on cash management account)
• Auto-invest: Available
• Withdrawals: Instant
• FDIC insured: Yes (up to $6M)

Verdict: Mercury offers slightly higher yield (4.5% vs 4.0%). Brex offers instant withdrawals.

Features Comparison

Banking Features

Mercury:

• FDIC insurance: $5M (via Choice Financial Group, Evolve Bank)
• Checking accounts: Unlimited
• Savings accounts: Via Treasury (4.5% yield)
• Multi-user access: Yes (team members, roles)
• Sub-accounts: Create separate accounts for projects
• Bill pay: Yes
• Check writing: Yes

Brex:

• FDIC insurance: $6M (via partner banks)
• Checking accounts: Yes
• Savings accounts: Cash management (4.0% yield)
• Multi-user access: Yes (advanced roles)
• Sub-accounts: Not available
• Bill pay: Yes (advanced)
• Check writing: Yes

Verdict: Roughly equal; both offer solid banking features.

Corporate Cards

Mercury:

• Card type: Debit cards (spend your own money)
• Credit limit: N/A (limited by account balance)
• Approval: No credit check required
• Virtual cards: Yes (create instantly)
• Physical cards: Yes (free)
• Spending controls: Basic limits
• Rewards: None

Brex:

• Card type: Credit cards (30-day payment terms)
• Credit limit: Based on cash balance + revenue (typically 10-20x monthly revenue)
• Approval: No personal guarantee required (uses company financials)
• Virtual cards: Unlimited (create instantly)
• Physical cards: Yes (free, premium metal cards)
• Spending controls: Advanced (merchant locks, limits, approvals)
• Rewards: 1-7x points on various categories

Brex Rewards Breakdown:

• 7x points: Rideshare (Uber, Lyft)
• 4x points: Software subscriptions
• 3x points: Restaurants, travel
• 1.5x points: Recurring bills
• 1x points: Everything else

Points value: ~1 cent per point (redeem for statement credits, travel, gift cards)

Verdict: Brex wins decisively if you need credit and rewards. Mercury wins if you prefer simplicity and no credit.

Expense Management

Mercury:

• Receipt capture: Basic (upload via app)
• Categorization: Manual
• Approval workflows: Not available
• Reimbursements: Manual process
• Reporting: Basic transaction export
• Integration: QuickBooks, Xero

Brex:

• Receipt capture: Advanced (OCR, auto-match)
• Categorization: AI-powered automatic
• Approval workflows: Multi-level approvals
• Reimbursements: Built-in reimbursement system
• Reporting: Advanced dashboards, custom reports
• Integration: QuickBooks, Xero, NetSuite, Sage

Verdict: Brex wins decisively on expense management.

Integrations

Mercury:

• Accounting: QuickBooks Online, Xero
• Payroll: Gusto (automatic funding)
• Payments: Stripe (view balance)
• Banking: Plaid (connect to other apps)

Brex:

• Accounting: QuickBooks, Xero, NetSuite, Sage Intacct
• Payroll: Gusto, Rippling, ADP
• Travel: Navan (formerly TripActions)
• ERP: NetSuite, SAP
• Extensive API: Build custom integrations

Verdict: Brex wins on breadth of integrations.

Credit and Underwriting

Mercury: No Credit, No Problem

Underwriting:

• No credit check
• No personal guarantee
• No revenue requirements
• Approval based on: Business registration, founders' identity

Advantages:

• Fast approval (24-48 hours)
• No credit impact
• Perfect for pre-revenue startups

Disadvantages:

• Debit cards only (no credit)
• Limited by cash balance

Brex: Credit Without Personal Guarantee

Underwriting:

• No personal guarantee required (unique!)
• No personal credit check
• Based on: Cash balance, revenue, funding
• Credit limit: Typically 10-20x monthly revenue

Example credit limits:

• $500K cash, $100K/month revenue → $1-2M credit limit
• $2M cash, $500K/month revenue → $5-10M credit limit

Advantages:

• Access to credit without personal liability
• 30-day payment terms (float)
• Build company credit history

Disadvantages:

• Requires significant cash or revenue
• Not suitable for very early-stage startups

Verdict: Mercury for early-stage (no credit needed). Brex for funded startups (credit without personal guarantee).

Approval Process and Timeline

Mercury

Requirements:

• US-incorporated entity (C-Corp, LLC)
• EIN from IRS
• Certificate of Incorporation
• Founders' government ID

Timeline:

• Application: 15 minutes
• Approval: 24-48 hours (most startups)
• Account activation: Immediate

Approval rate: ~90% for legitimate US entities

Brex

Requirements:

• US-incorporated entity
• EIN from IRS
• Certificate of Incorporation
• Founders' government ID
• Bank statements (to assess cash position)
• Revenue data (if applicable)

Timeline:

• Application: 20-30 minutes
• Approval: 1-3 business days
• Card arrival: 7-10 business days

Approval rate: ~70-80% (stricter due to credit offering)

Verdict: Mercury is faster and easier for early-stage startups.

Real-World Use Cases

Choose Mercury If:

Scenario 1: Pre-Seed Startup

• Just incorporated via Stripe Atlas
• Raised $100K-$500K (or bootstrapped)
• Team of 1-5 people
• Need simple, free banking

Why Mercury:

• No credit check (approved in 24 hours)
• Free domestic wires (pay contractors)
• 4.5% yield on idle cash
• Simple, clean interface

Scenario 2: Bootstrapped SaaS

• $50K-$200K ARR
• Profitable, no outside funding
• Don't need credit
• Want to maximize savings on banking fees

Why Mercury:

• $0 fees (free wires, ACH, everything)
• Treasury yield (earn 4.5% on cash)
• No minimum balance
• Perfect for lean operations

Choose Brex If:

Scenario 1: Seed-Funded Startup

• Raised $2M-$5M seed round
• Team of 10-30 people
• High monthly spend ($100K+)
• Want rewards on spend

Why Brex:

• Credit cards with 1-7x rewards
• No personal guarantee
• Advanced expense management
• Earn points on software, ads, travel

Example: $100K/month spend = 150,000 points/month = $1,500/month value = $18,000/year in rewards

Scenario 2: Series A+ Startup

• Raised $10M+ Series A
• Team of 50+ people
• Complex expense management needs
• Want enterprise-grade features

Why Brex:

• Multi-level approval workflows
• Advanced reporting and analytics
• NetSuite integration
• Dedicated account manager

Cost-Benefit Analysis

Scenario: Startup with $50,000/month spend

Mercury:

• Banking fees: $0
• Wire fees: $0 (domestic)
• Card rewards: $0
• Total cost: $0
• Net benefit: $0

Brex:

• Banking fees: $0
• Wire fees: $0 (up to 20/month)
• Card rewards: ~$750/month (1.5% average on $50K spend)
• Total cost: $0
• Net benefit: +$750/month ($9,000/year)

Verdict: Brex provides $9,000/year in rewards for high-spend startups.

Scenario: Startup with $10,000/month spend

Mercury:

• Banking fees: $0
• Net benefit: $0

Brex:

• Banking fees: $0
• Card rewards: ~$150/month
• Net benefit: +$150/month ($1,800/year)

Verdict: Brex still provides value, but less significant for lower spend.

Frequently Asked Questions

Which is better for early-stage startups?

Mercury for pre-seed and seed startups with <$1M raised. No credit check, fast approval, free banking.

Which is better for funded startups?

Brex for seed+ startups with $2M+ raised and $50K+/month spend. Rewards and credit make it worthwhile.

Can I use both?

Yes! Many startups use:

• Mercury: Primary banking (free wires, Treasury yield)
• Brex: Corporate cards (rewards, expense management)

Does Brex require a personal guarantee?

No! This is Brex's biggest advantage. Credit cards without personal liability.

Which has better customer support?

Mercury: Faster response times, better for early-stage
Brex: Dedicated account managers for larger customers

Can I get approved for Brex without revenue?

Yes, if you have significant cash ($500K+). Brex underwrites based on cash + revenue.

Which has better Treasury/savings yield?

Mercury: 4.5% APY (slightly higher)
Brex: 4.0% APY (but instant withdrawals)

Are the rewards worth it on Brex?

Yes, if you spend $50K+/month. At that level, you'll earn $9,000+/year in rewards.

Pros and Cons

Mercury Pros

✅ Completely free (no fees on anything)
✅ Fast approval (24-48 hours)
✅ No credit check required
✅ Free unlimited domestic wires
✅ 4.5% Treasury yield
✅ Simple, clean interface
✅ Perfect for early-stage startups
✅ $5M FDIC insurance

Mercury Cons

❌ Debit cards only (no credit)
❌ No rewards program
❌ Basic expense management
❌ Limited integrations vs Brex
❌ 1% foreign transaction fee

Brex Pros

✅ Credit cards without personal guarantee
✅ 1-7x rewards on spending
✅ Advanced expense management
✅ Unlimited virtual cards
✅ Extensive integrations (NetSuite, etc.)
✅ $6M FDIC insurance
✅ Premium metal cards

Brex Cons

❌ Requires cash or revenue for approval
❌ Limited free domestic wires (20/month)
❌ 2.7% foreign transaction fee
❌ More complex interface
❌ Lower Treasury yield (4.0% vs 4.5%)

Final Verdict

Mercury: Best for Early-Stage Startups

Rating: ⭐⭐⭐⭐⭐ (5/5) for pre-seed/seed

Choose Mercury if:

• You're pre-seed or early seed stage
• You don't need credit
• You want the simplest, free banking
• You prioritize low fees over rewards
• You're bootstrapped or have <$1M raised

Bottom line: Mercury is the best free banking option for US startups. Perfect for early-stage companies that don't need credit.

Brex: Best for Funded Startups

Rating: ⭐⭐⭐⭐½ (4.5/5) for funded startups

Choose Brex if:

• You've raised $2M+ in funding
• You spend $50K+/month
• You want rewards on spending
• You need advanced expense management
• You want credit without personal guarantee

Bottom line: Brex's rewards and credit make it ideal for funded startups with high spend. The 1-7x rewards can generate $10,000+/year in value.

The Hybrid Approach

Many startups use both:

1. Mercury: Primary banking account (free wires, Treasury yield)
2. Brex: Corporate cards for team spending (rewards, expense management)

How it works:

• Keep main cash in Mercury (earn 4.5% yield)
• Transfer to Brex as needed for credit card payments
• Use Brex cards for all spending (earn rewards)
• Use Mercury for wires and ACH (free)

Ideal for: Funded startups ($2M+) with $50K+/month spend.

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Disclosure: This review is based on independent testing and research. We may earn a commission if you sign up through our links, but this does not influence our editorial assessment.