Mercury

What Mercury is, in 2026

Mercury is a digital business-banking platform built for US-incorporated startups, SMBs, and freelancers. Approximately 200,000 business customers as of early 2026, with disproportionate representation among Y Combinator cohorts. Founded 2017, headquartered in San Francisco, and structurally a fintech rather than a chartered bank.

Free Standard tier (where most customers stay) and Mercury IO at $35/mo for higher transaction limits, custom workflows, and bookkeeping integrations. Mercury Treasury, managed via Apex Clearing into Vanguard and BlackRock money-market funds, lets idle cash earn yields that have tracked the federal-funds rate closely — currently quoted up to 5.00% APY net of fees, though the rate is variable and re-prices with the underlying T-bill yield curve.

Two structural facts to hold together: Mercury is not a bank, and Mercury deposits are FDIC-insured up to $5M. Both are true, and the rest of the review is about how that works.

At a glance

Who Mercury is for: US-incorporated startups (Delaware C-Corp or LLC) and SMBs, particularly those with venture funding, technical co-founders who want API access, or operating-cash balances above the $250K FDIC ceiling at a single bank. Y Combinator cohorts have used Mercury as a default since roughly 2019, and the founder-friendly onboarding path is well-trodden — most well-formed C-Corp applications clear in under one business day.

Who to avoid Mercury for: sole proprietors who have not incorporated; non-US entities (no UK Ltd, no Pty Ltd, no SARL); founders resident in jurisdictions Mercury de-onboarded in 2024; businesses that need cash-deposit infrastructure (Mercury supports no in-person cash deposit); and any operator who prefers a single chartered bank relationship over a partner-bank stack with an extra operational link in the chain.

Safety in one sentence: deposits are FDIC-insured pass-through up to $5,000,000 per customer when enrolled in the IntraFi sweep, distributed across roughly twenty FDIC-insured partner banks in $250,000 buckets, with the standard $250,000 ceiling applying to non-sweep balances at any individual partner bank.

Bank structure & deposit protection

The structural question is the one to get right. Mercury Technologies, Inc. is not a chartered bank. It is a financial-technology company that operates a business-banking experience for US startups on top of FDIC-insured partner banks. Customer funds sit at Choice Financial Group, N.A. (FDIC certificate #21102), Evolve Bank & Trust (FDIC certificate #1299), and Patriot Bank, N.A. (FDIC certificate #34134), with additional sweep-network banks rotating in and out of the IntraFi allocation list. Mercury holds no banking licence and does not lend against customer deposits — it is the technology and customer-experience layer sitting on top of a chartered-bank stack.

The partner-bank model means the FDIC counterparty is the partner bank, not Mercury. If Mercury Technologies, Inc. were to enter financial distress as a corporate entity, customer deposits would not be exposed to Mercury’s creditors — the funds are titled at the partner bank in the customer’s name (or in an FBO custodial account titled for the customer’s benefit) and would remain accessible. This is the structural premise of every BaaS arrangement, and Mercury’s contractual disclosure of it sits in the account agreement and in the Mercury Vault program disclosure.

The differentiating feature is Mercury Vault, which extends FDIC pass-through cover to $5,000,000 per customer by enrolling deposits in the IntraFi (formerly ICS / CDARS) deposit network. IntraFi auto-distributes customer balances across roughly twenty FDIC-insured banks in $250,000 buckets — each bucket sits at a different bank and qualifies for full FDIC coverage in its own right. The customer sees a single Mercury Vault balance; underneath, the funds are spread across the network.

Two pre-conditions apply to the $5M figure. First, the customer must opt in to the sweep program — non-sweep balances at a single partner bank are capped at the standard $250,000 ceiling. Second, the customer must monitor for partner-bank overlap: if you already hold deposits at one of the IntraFi-network banks under your own banking relationship, those balances aggregate against the $250,000 ceiling for that bank. Verify the current allocation list against your other banking relationships before treating the headline figure as load-bearing for treasury policy.

Mercury Treasury yields are NOT FDIC-insured. Treasury holdings are investment products — short-duration Treasury bills and money-market funds — held in customers’ brokerage accounts at Apex Clearing Corporation. Brokerage cash is protected by SIPC up to $500,000 (with a $250,000 cash sub-limit), which covers custodian failure rather than market loss. The distinction matters: a customer who moves $1M from Mercury Vault to Mercury Treasury moves the same dollars from FDIC-insured deposit cover to SIPC-covered investment holdings, and the legal protection regime changes accordingly.

The Synapse footnote. Mercury was not a Synapse customer for retail or business-deposit flows. Synapse was a banking-as-a-service middleware that connected fintechs like Yotta, Juno, and Copper to partner banks; when Synapse entered bankruptcy in May 2024, those middleware-dependent fintechs lost access to the ledger that mapped customer balances to bank-level FDIC pass-through, and customers were locked out of their funds for months. Mercury runs its own ledger and contracts directly with its partner banks, which is why the Synapse collapse did not freeze Mercury balances. Industry coverage routinely conflates the two stories because both involve fintech-via-partner-bank — the distinction matters because it is the entire reason Mercury balances stayed liquid through the Synapse event.

The fee schedule

Mercury’s pricing is one of the simpler schedules in the US business-banking category. The Standard tier is free with no minimum balance, no monthly fee, and unlimited domestic ACH. Mercury IO at $35/mo unlocks higher transaction limits, custom approval workflows, deeper accounting integrations, and dedicated support routing. The fee surfaces that matter for a typical operating account are wires, FX, and Treasury-management fees on idle-cash yield.

The Treasury 0.20% AUM is the headline cost most operators miss when comparing Mercury to a direct money-market-fund holding at Vanguard or Fidelity. On a $1M Treasury balance, that fee is $2,000 per year — meaningful versus a self-directed brokerage at zero fee, and the right line item to model when deciding how much idle cash to route into Mercury Treasury versus sweep deposits or an external broker. The $5 international-wire fee is competitive for the category but the ~1% FX markup is not — operators sending material cross-border volume should compare against Wise Business or a dedicated FX desk before defaulting to Mercury for outbound international flows.

Hands-on notes

The application flow for a Delaware C-Corp is fast — typically 10–20 minutes to submit, with a same-day decision when documents are clean. The required artefacts are predictable: certificate of incorporation, IRS EIN letter, beneficial-ownership disclosure (FinCEN-style 25%-or-more rule), and ID for each beneficial owner. Stripe Atlas, Firstbase, and Clerky-style incorporation kits typically include everything Mercury asks for, which is part of why the onboarding feels paved for the YC-pattern founder.

The first physical debit card arrives in 5–10 business days; virtual cards are available immediately on signup with sub-card limits and category controls. Multi-user access is granular — admin, bookkeeper, and custom roles — and the audit log captures sign-in, transfer, and approval events at the resolution most accountants want for SOC 2 evidence. Bookkeeping integrations cover QuickBooks Online, Xero, and NetSuite as the headline trio; Brex Empower and Ramp are not direct integrations (they are competitors) but a CSV export path exists for operators bridging stacks.

Treasury setup is a separate mini-onboarding inside the same dashboard. Customers complete a short suitability questionnaire and a sub-application that opens a brokerage account at Apex Clearing — this is where the FDIC-to-SIPC regime change happens, and Mercury makes the distinction explicit at the enrolment screen rather than burying it in disclosure. Funds can be moved between Mercury Vault (FDIC sweep) and Mercury Treasury (Apex brokerage) on demand; the operational pattern most well-funded startups use is to keep 60–90 days of payroll in Vault and the rest in Treasury, with a top-up rule that auto-moves Treasury yields back into Vault when the operating balance dips.

The API is one of Mercury’s structural differentiators. Read-only API access ships on the Standard tier (account balances, transaction history, statements); write access (create transfers, originate wires, manage cards) is gated behind Mercury IO. Stripe webhooks plug in directly for revenue ingestion; QuickBooks Online and Xero pull the same transaction stream via the integration layer. Most engineering-led startups end up with a Mercury-to-Slack notification bot for outbound transfers within the first quarter.

Friction points that show up in actual usage. Cash deposits are unsupported — there is no Allpoint deposit network and no in-person branch path. International receipts come via SWIFT with intermediary-bank fees that are not always pre-disclosed. Outbound international wires work to most countries but settle on T+1 to T+3 depending on corridor, and the FX markup is visible only at the confirmation screen rather than in the app’s landing surface. Customer support is in-app chat plus email; phone support is not offered, which is usual for the category but worth flagging for operators coming from a relationship-banker model.

Plan & tier comparison

Mercury’s tier line-up is narrower than most consumer neobanks because the product is business-only and the differentiator sits in account features rather than card perks. The decision is genuinely binary for most teams: Standard until a transaction-volume or workflow-control threshold is reached, then IO when team size and approval discipline justify the $35/mo.

Mercury Treasury sits alongside both tiers as an opt-in product rather than a tier itself. The yield is variable and re-prices with the underlying T-bill curve net of the 0.20% management fee — operators planning treasury policy on the headline number should model the post-fee net yield against the holding period, because the management fee compounds against shorter-dated paper. Mercury Bills (AP automation) and Mercury Pay (mass-payouts) sit on top of both tiers with usage-based pricing for high-volume payouts; the API access gating is the operational line that pulls technical teams onto IO.

Caveats

Non-US founders face real friction. Mercury onboards US-incorporated entities only — no UK Ltd, no SARL, no Pty Ltd. International founders typically incorporate a Delaware C-Corp or LLC first via Stripe Atlas, Firstbase, or Clerky and then apply, which adds incorporation cost (\\$500–\\$1,000) and ongoing US tax filings (Form 5472, Form 1120-F where applicable). The path is well-trodden but it is not free.

August 2024 jurisdiction de-onboarding. Mercury announced in August 2024 that it would close accounts associated with a list of higher-risk jurisdictions, citing partner- bank compliance posture and BSA/AML risk. The list shifted through Q4 2024 and into 2025; operators incorporating around Mercury should verify their country of residence is currently supported before committing. This is the single most-asked support topic in non-US founder communities, and the answer is jurisdiction-specific and time-sensitive.

Treasury yields are NOT FDIC-insured. This bears repeating because it is the most-misread line on the dashboard. Mercury Treasury balances sit in a brokerage account at Apex Clearing, protected by SIPC up to $500,000 (with a $250,000 cash sub-limit), and exposed to market risk from the underlying T-bill or money-market-fund position. Operators should not park more than the SIPC ceiling in Treasury cash awaiting investment without understanding the regime difference.

The IntraFi sweep cap is not a hard cap on deposits — it is a hard cap on insurance. Funds above the $5M sweep ceiling are not rejected; they are held at partner banks but become uninsured above the per-bank $250,000 ceiling for any non-distributed slice. Operators with operating-cash balances above $5M should structure across multiple banking relationships rather than rely on a single Mercury Vault for the full balance.

Operational fragility from the BaaS stack. The 2024 Evolve Bank & Trust ransomware incident did not affect FDIC coverage but did disrupt some Evolve-fronted fintech operations, and the Synapse collapse — although it did not affect Mercury — reinforced the structural lesson that multi-party banking-as-a-service has more operational links in the chain than a direct chartered-bank relationship. The trade-off is real; the FDIC coverage posture is materially stronger, the operational risk surface is materially wider.

Mercury vs. Brex vs. Bluevine

The closest US structural competitors are Brex (corporate-card-led, partner-bank checking) and Bluevine (high-yield business checking, partner-bank model). The three solve overlapping but distinct problems for US business banking, and many startups end up running two of the three in parallel rather than choosing one.

Mercury vs. Brex. Brex is corporate-card-first: the entry point is the Brex Card, and the spend-management plus AP-automation tooling around it is deeper than Mercury’s. Brex Cash sits at Choice Financial Group, Lead Bank, and Citi, with FDIC pass-through quoted up to $6M. Brex pivoted toward mid-market and enterprise from 2022, deprecating SMB onboarding for a period, and is now back open to seed-stage startups but with a more enterprise-flavoured product surface. Mercury is checking-first with a card product attached; the API access and the YC-cohort default-status are Mercury’s structural advantages over Brex for venture-funded technical startups.

Mercury vs. Bluevine. Bluevine is a US business-banking product targeting lower-mid-market SMBs, with a high-yield checking proposition (rate has tracked above 2% APY on qualifying balances) and partner-bank FDIC pass-through. Bluevine’s differentiator is the yield on the operating balance itself rather than via a separate sweep or treasury product; Mercury keeps the operating balance flat at the FDIC ceiling and routes idle cash to Vault sweep or Treasury. For an SMB that wants yield without moving funds between products, Bluevine is structurally simpler. For a startup that wants segregated operating, sweep, and treasury allocations, Mercury is structurally cleaner.

FAQ

Is Mercury a real bank?

No. Mercury Technologies, Inc. is a fintech, not a chartered bank. Customer deposits sit at FDIC-insured partner banks: Choice Financial Group, N.A., Evolve Bank & Trust, and Patriot Bank, N.A. The FDIC insurance is real and pass-through, but the legal counterparty is the partner bank, not Mercury.

How does Mercury get to $5M of FDIC pass-through?

By enrolling sweep-eligible deposits in the IntraFi (formerly ICS / CDARS) network. IntraFi auto-distributes balances across roughly twenty FDIC-insured banks in $250,000 buckets, so a $5M Mercury Vault balance appears as twenty separate $250,000 deposits, each with its own FDIC coverage. Coverage requires opt-in and is reduced by overlap with other banking relationships at IntraFi-network banks.

Was Mercury affected by the Synapse collapse?

No. Mercury was not a Synapse customer for retail-deposit flows. Synapse was middleware for fintechs like Yotta and Juno; when it entered bankruptcy in May 2024, those middleware- dependent fintechs lost their ledger. Mercury runs its own ledger and contracts directly with its partner banks, which is why customer funds were unaffected.

Are Mercury Treasury yields FDIC-insured?

No. Treasury is an investment product — T-bills and money-market funds held in a brokerage account at Apex Clearing — protected by SIPC up to $500,000 (with a $250,000 cash sub-limit), not FDIC. Customers who need FDIC cover for the same balance should hold it in Mercury Vault sweep, not Mercury Treasury.

Can non-US founders open a Mercury account?

Mercury onboards US-incorporated entities only. International founders typically incorporate a Delaware C-Corp or LLC first (Stripe Atlas, Firstbase, Clerky) and then apply. Mercury announced jurisdiction-specific account closures in August 2024 — verify that your country of residence is currently supported before incorporating.

How does Mercury compare with Brex?

Brex is corporate-card-first with deep spend-management and AP automation. Mercury is checking-first with API access and treasury yield. For a venture-funded startup that wants corporate cards plus spend control, Brex is the structural fit. For a startup that wants a primary operating account and FDIC pass-through on idle cash, Mercury is the fit. Many startups run both.

What happens if Choice Financial Group or Evolve Bank fails?

Sweep-enrolled balances are spread across roughly twenty FDIC-insured banks in $250,000 buckets, so the failure of any one partner bank limits the at-risk slice to $250,000 per customer at that bank. FDIC resolution would pay out within the statutory window. The 2024 Evolve ransomware incident did not impact FDIC coverage but did highlight the operational- fragility tradeoff inherent to multi-party banking-as-a-service stacks.

Who Mercury is for

Use Mercury if you run a US-incorporated startup or SMB, want zero-fee business checking with FDIC cover beyond $250,000 via the IntraFi sweep, value the API-first developer experience, and do not need a multi-currency operating account. It is the structural default for US YC-pattern startups for a reason — the onboarding path, the FDIC pass-through ceiling, and the API surface together cover the operating-account decision for most venture-funded technical teams.

Use a chartered alternative or a traditional business bank if you want a single direct-charter counterparty rather than a partner-bank stack, if you need branch banking or cash deposit, if you are not US-incorporated and incorporating is not on the roadmap, or if your treasury policy requires investment-product yield access that you would rather hold at a dedicated broker than via Apex Clearing inside Mercury.

References

Primary-source list, with capture date 2026-04-29. Mercury’s legal surface and the IntraFi participation list shift across quarters; any operator treating these figures as load-bearing for treasury policy should re-verify against the source URLs at decision time.

• Mercury — Legal & disclosures (Mercury Vault, IntraFi sweep)
• Mercury — Account agreement & sweep program disclosure (Choice Financial Group)
• IntraFi — Network deposits (formerly ICS / CDARS) overview
• FDIC BankFind — Choice Financial Group, N.A. (FDIC cert. #21102)
• FDIC BankFind — Evolve Bank & Trust (FDIC cert. #1299)
• FDIC BankFind — Patriot Bank, N.A. (FDIC cert. #34134)
• FDIC — General Counsel’s opinion 8: pass-through deposit insurance
• Bloomberg — Synapse collapse leaves Yotta, Juno, others without funds (May 2024)
• Wall Street Journal — Synapse bankruptcy and the fintech middleware risk (June 2024)
• American Banker — Evolve Bank & Trust ransomware incident (June 2024)
• TechCrunch — Mercury closes accounts in select non-US jurisdictions (Aug 2024)
• SEC EDGAR — Apex Clearing Corporation Form CRS (custodian for Mercury Treasury)

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