Mercury vs Brex for Seed-Stage SaaS (2026): Bank Account vs Spend Platform, Fees, Yield and Ownership
Pick Mercury if you are pre-revenue or not yet funded, want a business bank account first and a flat 1.5% cashback card second, and your team is small enough that per-user software fees would bite. Pick Brex if you have raised money and hold at least $50,000 (or bill more than $500,000 a year), want expense policies, travel and multi-entity cards in one tool, and want a treasury product with no minimum balance. At seed both cost almost nothing in fees on our activity profile; the money is in yield on idle cash, where Brex posts a higher rate at every balance tier, but the two rates are not computed the same way. Brex has been owned by Capital One since April 7, 2026. Mercury has a preliminary national bank charter approval and is not yet a bank.
The two start from opposite ends: Mercury is a bank account with a card, bill pay and treasury on top; Brex is a card and spend platform (expenses, travel, bill pay) with an account and treasury attached.
What each costs at pre-seed, seed and Series A
| Stage | Mercury fees a year | Mercury IO cashback | Mercury Treasury yield | Brex Essentials fees a year | Brex Premium seats | Brex Treasury yield |
|---|---|---|---|---|---|---|
| Pre-seed | $504 ($360 FX on non-USD wires, $144 card FX) | $648 | $11,480 (3.28%) | $144 card FX, plus FX on non-USD wires (not published) | $432 | $12,635 (3.61%) |
| Seed | $3,600 ($2,880 FX on wires, $720 card FX) | $3,240 | $85,750 (3.43%) | $720 card FX, plus FX on wires (not published) | $1,440 | $92,750 (3.71%) |
| Series A | $18,720 ($14,400 FX on wires, $4,320 card FX) | $12,240 | $363,000 (3.63%) | $4,320 card FX, plus FX on wires (not published) | $4,320 | $376,000 (3.76%) |
Activity profile is our assumption for a B2B SaaS startup: pre-seed $500K cash ($150K operating), 2 domestic wires and 1 non-USD payment of $3,000 a month, $4,000 card spend (10% non-USD), 3 users; seed $3M ($500K), 6 wires, 4 x $6,000, $20,000 card (10%), 10 users; Series A $12M ($2M), 15 wires, 12 x $10,000, $80,000 card (15%), 30 users. Card FX at the published 3% ceiling for both. Yield on idle cash (cash minus operating). Mercury: Mercury Treasury in the State Street government money market fund MRGXX, net of Mercury's fee, 7-day effective SEC yield as of October 12, 2026. Brex: "total treasury return" on the DGVXX government money market fund plus Brex's additional return, by total balance, no as-of date printed (DGVXX 7-day yield 3.50% read October 13, 2026). Brex points are not in the table because Brex has no flat rate. Computed in our banking cost model.
At seed, Mercury's fees ($3,600) are roughly cancelled by IO cashback ($3,240), while idle cash earns $85,750 at Mercury and $92,750 at Brex. Two caveats on that $7,000 gap. Brex changed its headline method between September 2 and October 3, 2026, from an annual rate on the 7-day yield (top tier 3.71%) to an "annualized compounded" figure (top tier 3.91%), so part of the rise is method, not rate. And Brex sets the FX rate on non-USD wires "at our sole discretion" with no published markup, against Mercury's stated 1%: ask Brex for its margin in writing if you pay people abroad. Run your own numbers, or see every provider in startup banking costs by stage.
Published prices
| Plan | Price (monthly / billed yearly) | For / limits |
|---|---|---|
| Mercury | $0/mo | 'Powerful banking and finance essentials included with every account': checking and savings, free ACH, domestic and USD international wires, RTP, checks, debit cards, IO card, bill pay, invoicing, QuickBooks/Xero sync; Reimbursements for up to 5 active users per month (pricing FAQ: paid plan needed for 'reimbursing out-of-pocket expenses for more than 5 active users per month') |
| Mercury Plus | $35/mo monthly or $29.90/mo billed annually (15% off) | Recurring invoices, invoice with ACH debit ($1/transaction), unlimited 1099 tax filings, $50 off eligible LegalZoom Compliance Plans, 6 months free Xero |
| Mercury Pro | $350/mo monthly or $299/mo billed annually (15% off) | Relationship manager, invoice with ACH debit ($0/transaction), NetSuite categorizations, unlimited 1099 tax filings |
| Add-on: ACH, domestic wires, real-time payments, checks (send and receive) | $0 on all plans | RTP only for accounts on Column N.A. (pricing footnote and help article 43065703960852) |
| Add-on: USD international wire (outgoing) | $0 (SHA); $15 flat to send as OUR so Mercury covers intermediary fees | Pricing FAQ and help article 28773111244436 |
| Add-on: Non-USD international wire (outgoing) | 1% currency exchange fee | Pricing table and help article 28772836414228 ('The exchange includes a 1% currency conversion fee'); negotiable above $200K/month exchanged |
| Add-on: Incoming non-USD wire | No Mercury fee stated; Column N.A. converts at mid-market, Choice uses intermediary banks that 'typically add a 2-3% markup' | Help article 34750478414740. USD-only accounts: incoming non-USD is converted to USD. |
| Add-on: Non-USD card transactions (debit and IO) | 3% currency exchange fee | Pricing compare table and help article 32529650270484; also applies to non-USD ATM withdrawals; not refunded; excluded from cashback |
| Add-on: IO card cashback | 1.5% cashback on all settled purchases | Charge card issued by Patriot Bank, N.A.; cash-underwritten (balance cannot exceed Mercury cash); daily repayment until $15K total Mercury balance, then monthly; no annual fee. Cashback paid when the balance is repaid. |
| Add-on: Mercury Treasury | Advisory fee 0.15%-0.60%/yr of Treasury positions by total Mercury deposits ($0-2M 0.60%, $2-5M 0.45%, $5-10M 0.35%, $10-20M 0.25%, >$20M 0.15%); minimum $250K total Mercury balance | Net yields as of 2026-10-09/10-12 on mercury.com/treasury: MRGXX (State Street govt MMF, 7-day effective SEC yield as of 10/12/2026) 3.28% at $250K-$2M, 3.43% $2-5M, 3.53% $5-10M, 3.63% $10-20M, 3.73% $20-50M; MCRYX (Morgan Stanley ultra-short bond, floating NAV, not an MMF, 30-day effective yield as of 10/09/2026) 3.60% / 3.75% / 3.85% / 3.95% / 4.05%. Not FDIC insured; SIPC via Apex Clearing. |
| Add-on: Mercury Books | $35/mo, waived until Dec 31, 2026 | Shown under the free plan on the pricing page |
| Add-on: 1099 filing (free plan) | $5/filing | Unlimited on Plus and Pro |
| Add-on: Invoicing ACH debit (receiving) | $1/transaction on Plus, $0 on Pro | Card payments on invoices via Stripe fees |
| Add-on: Mercury Personal | $240/year, included free with an active Business account | Pricing page and FAQ |
Prices verified on mercury.com/pricing on October 13, 2026.
| Plan | Price (monthly / billed yearly) | For / limits |
|---|---|---|
| Essentials | $0 user/month | Startups and growing companies: global card, 1 local card program, up to two entities, accounting integrations, local currency wires, travel booking, bill pay, reimbursements, API; US EIN, US incorporation, US operations and US physical address; equity funding of any amount (with $50,000 minimum cash for funded startups) or more than $500,000 annual revenue |
| Premium | $12 user/month | Mid-sized companies: multiple expense policies, multi-entity US and international, ERP and HRIS integrations, VAT documentation, live budgets |
| Enterprise | Custom pricing | Unlimited US or global entities, local card issuance, named account manager |
| Add-on: Business account transfers | $0 ACH (domestic and international), checks, domestic and international wires, incoming and outgoing | brex.com/product/cash-management-account/rates-fees. Recipient's bank may charge. Non-USD wires: Brex chooses the FX rate 'at our sole discretion' (no markup published). Inbound international wires in USD only. |
| Add-on: Card foreign transaction / conversion fee | Up to 3% | Card Terms 1.6: markups 'typically equal to up to three percent (3%) of the Charge amount'; help center: 'will not exceed 3%'. |
| Add-on: Card late fee | 2.99% of the delinquent balance or $38, whichever is higher | Once per statement 30 days past due (Card Terms). |
| Add-on: Brex points | 1x to 8x points per USD by category; 1 point = 0.6 cent as cash or statement credit, 1 cent on Brex travel | Default Brex Exclusive (monthly payments): rideshare 7x, Brex travel 4x, restaurants 3x, recurring software 2x, everything else 1x. Daily payments [Software]: software 3x; [Advertising]: ads 1.5x. Points only on USD transactions with US merchants. Cash equivalent at 0.6 cent: 0.6% base, 1.2% software (monthly), 1.8% software (daily). Custom flat-rate rebates for 50+ users with spend commitments. |
| Add-on: Treasury (DGVXX money market fund) | Total treasury return 3.56% to 3.91% by total balance (no as-of date printed; DGVXX 7-day yield 3.50% read 2026-10-13) | Tiers: under $500K 3.56%; $500K-$2M 3.61%; $2M-$5M 3.71%; $5M-$20M 3.76%; $20M+ 3.91% (DGVXX plus a Brex-paid additional return of 0 to 0.35%). Annualised compounded figure. No minimum. Brex Treasury LLC, FINRA/SIPC, not FDIC. No separate management fee stated by Brex; fund expenses are inside the fund yield (expense ratio not checked). |
| Add-on: Vault (FDIC sweep) | Up to $6M FDIC coverage through 24 program banks | Swept by Brex Treasury LLC; 'Funds are not FDIC-insured until they arrive at program banks.' Checking at Column N.A. covered up to $250,000 across all sub-accounts. Vault yield not stated. |
Prices verified on brex.com/pricing on October 13, 2026.
Mercury bills Plus and Pro monthly ($35, $350) or annually at 15% off ($29.90, $299 a month) per the Mercury pricing page. Brex's self-serve terms bill Premium at "$12 USD per active user per month" in arrears (Brex pricing page); the $15 monthly price on one third-party page (Eightx) is not on brex.com. Full detail in Mercury pricing and Brex pricing.
Five differences that matter to a seed-stage founder
1. Who qualifies
Brex requires a US EIN, US incorporation, US operations and a US physical address, and then one of: equity funding of any amount (with $50,000 minimum cash for funded startups), more than $500,000 a year in revenue, or a referral. The revenue bar was "more than $1 million" on every capture of Brex's requirements page through July 8, 2026 and $500,000 from August 20, 2026. Brex dropped small businesses without professional funding in 2022 (TechCrunch, June 17, 2022). Mercury's pricing page states no minimum balance; IO starts on daily repayment and moves to monthly at $15,000 in Mercury balances. Non-US founders hit friction at both: a Hacker News post reported a Mercury closure notice for "a non-US resident (Kyrgyzstan) with a US C-Corp" (March 27, 2026).
2. Cashback vs points
Mercury IO pays 1.5% cashback on settled purchases. It is a charge card with limits set from your Mercury balances, no personal guarantee and no credit check. Brex pays points: 1x general, 2x recurring software, 3x restaurants, 4x Brex travel, 7x rideshare on the default monthly-payment program, only on USD spend with US merchants. A point is worth 0.6 cent as cash and 1 cent on Brex travel, so 0.6% on general spend and 1.2% on software (1.8% on the daily-payment Software profile). Valued as cash, Mercury's flat 1.5% pays more on general spend (Brex 0.6%) and on software under monthly payments (Brex 1.2%); Brex pays more on software under daily payments (1.8%), restaurants (1.8%), Brex travel (2.4%) and rideshare (4.2%), by our arithmetic at 0.6 cent a point.
3. Foreign currency
On non-USD card spend Mercury charges 3% (not refunded, no cashback on the fee) and Brex "up to 3%". On payments Mercury charges 1% on non-USD wires (negotiable above $200,000 a month), $0 on USD international wires or $15 to send them as OUR. Brex charges $0 on all wires but picks the FX rate itself.
4. Where the cash sits, and treasury
Neither is a bank, and the FDIC says "nonbank companies themselves are never FDIC-insured". Mercury deposits sit at Choice Financial Group and Column N.A., with "up to $5M in FDIC insurance" through their sweep networks, subject to pass-through conditions. Brex checking is a deposit account at Column N.A. covered up to $250,000; Brex Vault sweeps cash to 24 program banks for "up to $6M" of coverage, and Brex notes funds "are not FDIC-insured until they arrive at program banks". Both treasury products are money market funds: SIPC (up to $500,000 including $250,000 cash) covers the custodian failing, not a fall in value, and neither is FDIC-insured. The 2024 Synapse bankruptcy (trustee estimate: a $65-96 million shortfall) is why the record-keeping behind pass-through coverage matters. Brex Treasury has no minimum; Mercury Treasury needs $250,000 at Mercury, a US entity and a business located in one of 12 listed countries, and charges 0.60% a year under $2M down to 0.15% above $20M (the yields above are net of it). Mercury's other option, MCRYX (3.60% at the lowest tier, as of October 9, 2026), is an ultra-short bond portfolio with a floating price, not a money market fund, so do not set it against Brex's figure.
5. Ownership and charter
Capital One announced it would buy Brex on January 22, 2026 for $5.15 billion in stock and cash and completed the deal on April 7, 2026. Brex LLC is now "a wholly owned subsidiary of Capital One, N.A.", but Brex checking still sits at Column N.A., so your balances are not Capital One deposits. Mercury applied for a national bank charter on December 19, 2025 and received OCC preliminary conditional approval for Mercury Bank, N.A. on April 24, 2026. FDIC and Federal Reserve approvals are pending and the bank is not open. Its IO card issuer, Patriot Bank, was under an OCC formal agreement from January 14, 2025 until the OCC terminated it on June 30, 2026.
Switching and lock-in
No contract on either free tier. Mercury's government fund pays out same day before 3pm ET; Brex Vault moves to checking in 1 to 2 business days. The switching cost is rewards and limits: Brex points are lost on closure, and both card limits follow your balances, so moving the cash shrinks the old limit first. Move recurring charges to the new card before the money.
Not hands-on tested yet: we have not opened an account with Mercury or Brex, which require a US company and identity checks. Fees and rates come from Mercury's and Brex's published pricing pages, fee schedules and help centers, read on October 13, 2026.
Frequently asked questions
Is Mercury or Brex better for startups?
Unfunded or pre-revenue: Mercury, because Brex requires funding (and $50,000 cash) or more than $500,000 in revenue. Funded and wanting expense policies and travel in one tool: Brex. Fees are close; yield and Brex's unpublished FX margin decide the rest.
Who owns Brex?
Capital One. The acquisition was announced on January 22, 2026 and completed on April 7, 2026. Brex checking deposits are still held at Column N.A.
Is Mercury a bank?
Not yet. Accounts are held at Choice Financial Group and Column N.A.; Mercury Bank, N.A. has OCC preliminary conditional approval (April 24, 2026) and had not opened as of October 13, 2026.
Does Brex charge for wire transfers?
No fee on domestic or international wires, incoming or outgoing, per Brex's fee schedule. Non-USD wires are converted at an FX rate Brex chooses, and the recipient's bank may charge its own fee.
What is the foreign transaction fee on Mercury and Brex cards?
Mercury charges 3% on non-USD debit and IO card transactions, and the fee earns no cashback. Brex's card terms allow up to 3%, and Brex points are not earned on non-USD transactions or at non-US merchants.
Related: Ramp vs Brex, Mercury vs Relay, Mercury alternatives. Whichever account holds the round, cash runway is the number to watch.