Mercury vs Relay: Two Business Cash Systems

Mercury is the stronger fit for a startup that sends domestic wires and may later invest surplus cash through Treasury. Relay is the stronger fit for a business that wants separate checking accounts for taxes, payroll and operating expenses. The Business Bank Index comparison describes the same split in emphasis: startup and treasury tools at Mercury, cash allocation across accounts at Relay.

Both offer a free plan, but the subscription is only part of the cost. Wire volume, the way customers pay invoices, the need for recurring workflows and the amount of cash kept in reserve can each change which platform offers more value. A business holding a large balance also has to distinguish interest on a deposit account from returns on an investment fund.

What each free plan does with operating cash

Mercury’s published pricing puts its base plan at $0 per month, shows Plus at $29.90 and Pro at $299 per month with annual billing selected, and lists ACH payments and domestic wires as free to send and receive. The base plan includes invoice creation and unlimited bill payments. Customers can pay a Mercury invoice by standard ACH transfer, wire or check without a Mercury collection fee; the ACH debit option built into an invoice requires Plus or Pro.

Relay’s plan page lists Starter at $0, Grow at $30 and Scale at a limited-time $90 per month instead of its regular $120; Starter and Grow allow up to 20 checking accounts per business, while Scale allows 50. The page lists variable savings APYs, dated September 17, 2026, of 1.19% on Starter, 1.87% on Grow and 3.21% on Scale. All plans include invoice creation and tracking, accounting integrations and spend controls.

Relay’s account allowance is useful when money for different obligations should remain visibly separate. A business could, for example, allocate receipts among operating, payroll and tax accounts without paying for Grow. Mercury also offers checking and savings accounts, but its clearest advantage for a business that moves money frequently is the combination of free domestic transfers and access to additional finance products as its cash position grows.

Payment routes change the free-plan calculation

The Relay deposit agreement charges $8 for an outgoing domestic wire on Starter and $5 on Grow or Scale; same-day ACH costs $1, $0.50 and $0 respectively, and an incoming wire costs $5 on every tier. Outgoing international SWIFT wires cost $25, $22 and $20 across those tiers, while the listed local-network route costs $5, $3 and $1.50. Online card payments cost 2.9% plus $0.30; pay-by-bank charges vary by tier and are capped per transaction.

Consider a hypothetical startup that sends two domestic wires a month and needs no paid workflows. Mercury’s base subscription and its domestic-wire charges would total $0; Relay Starter would incur $16 in outgoing-wire fees. At ten such wires, Relay Starter would cost $80, matching Grow’s $30 subscription plus $50 in wire fees. That break-even point covers wires alone: Grow could be worthwhile earlier if its workflow features or savings yield have value to the business.

International payments require a separate calculation. Mercury offers a standard international wire in US dollars without a sending fee, though an intermediary bank may deduct a fee from the recipient; its optional fee-covering route costs $15, and converting a non-dollar international wire carries a 1% fee. Relay instead publishes a charge for each international wire, with the amount depending on the route and plan. The cheapest route for a company therefore depends on currency and how the payment must arrive, not just the monthly plan price.

When a paid workflow is worth considering

Both platforms let a business create invoices on a free plan, while recurring invoices sit in paid tiers. Mercury Plus adds recurring invoices and customer payment by ACH debit from an invoice, with a per-transaction charge; Pro removes that ACH debit charge and adds a relationship manager and more accounting features. A company whose customers already pay by ordinary ACH transfer or wire may have little reason to upgrade solely for invoicing.

Relay Grow adds recurring invoices, batch vendor payments, bookkeeping automation and multi-step approvals. Scale adds bill-payment automation, cash-flow insights and a larger checking-account allowance, alongside lower charges for some payment routes. These upgrades address a different pressure point from Mercury Treasury: they can reduce the work of collecting, approving, categorizing and paying money that still belongs in the operating system. The relevant threshold is the company’s actual payment and approval workload, rather than its balance alone.

What a balance above $250,000 changes

Mercury Treasury’s terms set a $250,000 minimum balance across Mercury accounts for eligible customers and show annualized yields net of fees, dated September 25, 2026, of 3.11% for its government money-market fund and 3.51% for its ultra-short bond fund in the $250,000-to-$2 million deposit band. Treasury is available to qualifying US entities and has further eligibility restrictions, including exclusions for nonprofits and LLCs taxed as sole proprietorships.

Mercury Treasury holds mutual funds through a brokerage account, while Relay’s quoted APYs apply to savings deposits. The funds have different withdrawal timing: Mercury describes same-day access to the government money-market fund when a transfer is initiated by its cutoff, while the bond fund can take longer. Brokerage protection addresses missing assets if a brokerage fails; it does not turn an investment return into an insured deposit rate or protect against changes in fund value.

For a hypothetical company with $300,000 available throughout a year, applying the quoted rates as if they stayed unchanged gives roughly $9,330 from Mercury’s money-market fund or $10,530 from its bond fund. Relay Scale’s quoted APY gives about $9,630 on a constant $300,000 savings balance; a full year at the promotional subscription price would cost $1,080, leaving about $8,550 before other fees. These are illustrations rather than forecasts. The company would also need to keep enough readily available cash for bills and payroll, and the cited Mercury yield band depends on its qualifying deposit balance.

Which system fits the business

A startup with modest reserves and regular domestic wires has a clear cost case for Mercury’s base plan. A business that routinely reserves cash for several obligations can use Relay’s checking-account structure on Starter, then assess Grow when payment volume or recurring approval and vendor workflows justify the subscription. For a company with substantial surplus cash, the decision turns on how much belongs in accessible deposit accounts and whether Mercury’s investment funds suit the remainder. Account eligibility and the business’s actual payment routes can settle the choice before a headline yield does.