Mercury Bank vs Brex

Mercury goes way beyond the basics when it comes to the safety and protection of your funds. You get full control over ACH pulls, with the ability to approve, limit, or block them before any money leaves your account.

If something looks off, it gets flagged automatically, and nothing moves without your say-so. This is something super unique Mercury built and cuts out the risk of someone draining your account with just your routing and account numbers.

Even more impressive, Mercury offers up to $5M in FDIC insurance through its sweep network and partner banks. Instead of your funds sitting at a single institution, they are automatically spread across multiple FDIC‑insured banks, so your deposits stay protected up to that limit even if one of those banks fails.

With that, you don’t have to think about coverage limits or worry about losing access if a single institution goes down. That kind of protection is rare, and you actually see it pay off when other banks shut down or get acquired and the whole experience falls apart (e.g., when SVB shut down, a lot of our founder friends who raised money moved over to Mercury).

As it stands, Mercury is the largest and most dominant fintech banking layer with a $3.5 billion valuation and $650 million ARR. They've also raised from the most trusted VC's including Sequoia.

Mercury is now profitable as a company (both net income and EBITDA) and has been for more than three years.

With that, Mercury recently applied to be its own bank charter, which is super rare. To put it into perspective, most fintechs never get close to running their own fully regulated bank, so even applying for a national bank charter signals that Mercury is operating at a scale more on par with traditional banks.

If you have $250K in your account, you can enable Mercury's Treasury to earn interest on your cash.

You can set up auto-transfer rules like "transfer to Treasury" or "maintain target balance" that run automatically (daily, specific weekdays, or on set dates like the 1st/15th of the month). So they make it easier to actually earn higher interest rates on idle funds, effectively allowing you to treat your treasury money market account like your savings account.

And unlike other banking solutions, Mercury's Treasury feature is built core into the product, so it feels like it's just a savings account, instead of a tacked on investment account.

One of the nice things about Mercury's Treasury is that it lets you earn interest on the cash sitting in your account without hurting your day-to-day liquidity. You can keep a portion of your funds in a more liquid Treasury option (JTCXX) that still earns solid interest but can be transferred back to your checking account same-day if you need it.

Then you can put the majority of your cash into a higher-yield Treasury option (MULSX) that earns more, but takes 1–2 business days to transfer back.

In practice, this means most of your money stays optimized for better returns while you still have easy access to the funds you need for normal business expenses.

Mercury is exceptional when it comes to moving money, whether you are paying vendors or getting paid. It's one of our favorite reasons why we love Mercury, because it just makes the entire financial admin side of things in our business more enjoyable.

First, paying vendors actually doesn't feel like a chore when it comes to Mercury because they manage the admin that you'd normally have to do manually.

You can send vendors a secure form where they enter their own contact details and bank information, which Mercury then stores so you can pay them by ACH or wire in just a few clicks.

If a vendor sends you an invoice, it will also auto-pull in their details.

Mercury will then also automatically request their W-9, keep track of who has submitted one, and make 1099 filing much easier later on. This is crucial if you work with a lot of contractors.

Having vendor onboarding, payments, and tax paperwork all handled in one place is extremely rare for a bank!

And when it comes to checks, Mercury removes a lot of the manual work. You just fill out a short form, attach any PDFs like invoices or payment details, and Mercury prints the check, includes the attachments (up to 6 pages), and mails it for you.

It honestly feels less like writing checks and more like having an assistant handle it for you. This has come in super handy when we've needed to mail in forms to the government.

Mercury does not charge fees for domestic wires or USD international wires.

Mercury has one of the cleanest invoicing experiences we've used 👌 The user experience is SOOOO good, it makes invoicing feel like less of a chore.

You can quickly create and send invoices, accept payments through ACH transfer, wire transfer, or (if you connect Stripe) credit/debit cards plus Apple Pay and Google Pay, and you can track invoice status and payments right from your Mercury dashboard.

Mercury allows you to open up to 100 checking accounts and 100 savings accounts per business, at no additional cost.

So if you like to organize your money by different expenses such as operations, marketing, payroll, taxes, etc., you are able to do that, and you can even get a credit or debit account for each. Businesses who tend to like that "profit-first" approach appreciate this feature (although in general, the recommended way to set up spending for businesses is via an expense management software).

You can even set up “auto-transfer rules” that keep target balances (e.g. 30% payroll, 20% tax, etc.). Setting this up is incredibly easy and intuitive. That’s the beautiful thing about Mercury, everything is super seamless to use.

For example, for us, most of our cash stays in Treasury to earn interest only what’s needed for monthly operating expenses is moved into checking.

We keep a target balance, and if our balance ever falls below that number, money is automatically transferred. Transfers are scheduled on the 7th and 25th so that checking is topped up right before contractor payments. The point is, you can set this up totally custom for your business.

We choose to keep our federal tax account almost empty and it's only funded before before IRS payments, because otherwise you’re "wasting" money by letting cash sit there earning nothing instead of in Treasury.

If you have multiple businesses, you can set them all up within Mercury and easily jump switch views.

But, okay here’s when it gets crazy. Mercury also has Mercury Personal Banking, which gives you the same incredible user experience but for your personal banking. You can also toggle into your personal bank account from the same user login, which is fantastic.

When they launched Mercury Personal, it cost $240/year to use (and we paid it, because it was that good), but now they give Mercury Personal accounts for free to any Mercury Business users.

This means if you have a Mercury Business account, you can give all of your employees a Mercury Personal account, for free! It’s a fantastic perk because trust us, there is no better personal banking solution that is as smooth and solid as Mercury Personal.👌

With Mercury, you can set up user roles and permissions. For example, you can set who can initiate payments, vs who may only get "view only" capabilities.

There are 6 preset roles: Admin (Full Control), Employee, Accountant, Finance Lead, Money Mover, and Read Only.

This matters if you have different employees that you want to delegate financial admin.

You can also set approval rules, like for example, any payment over $10,000 must be approved by a founder. You can enable per payment approvals, set an amount threshold, and choose who needs to approve (a specific person or a group). Approvals work for all outgoing payments including bills, ACH, and wires.

You can also set up dual admin approvals (aka two admins need approval before money goes out). This isn’t just a tiny feature for approving invoices, it's a core way Mercury lets you structure who can move money and how, so you have real control and guardrails over cash.

It's no secret that Mercury absolutely takes the cake when it comes to user experience. Many users have called Mercury's interface as "one of the best I've ever seen". It's modern, intuitive, and just feels incredibly smooth to use.

And that has been our personal experience using Mercury for the past several years, there is no way you can get us to switch after experiencing such beauty 😍

With Brex Vault, deposits can receive up to $6M in FDIC insurance through it's network of partner banks, and you can set basic controls around incoming ACH debits to reduce the risk of unauthorized transfers.

That said, the overall setup of it all feels more like it was tacked on to check a box, that is banking, versus them actually trying to innovate and set a new standard in the space.

The biggest concern right now is that there's quite a bit of long-term uncertainty here around Brex because they were acquired by Capital One, which could eventually lead to the product being folded into Capital One's more outdated banking stack. In-fact, many startup founders and business owners we know have moved off Brex since this announcement.

So while Brex is technically safe and secure as a platform, it doesn't feel quite as focused or purpose-built around the core banking experience as Mercury, and there's a lot of uncertainty around it right now especially.

Brex lets you earn some yield on idle cash, but the setup is fairly basic. Funds are placed into a government money market fund (DGVXX), and you can move money between checking and treasury without too much friction.

The main downside is that Brex essentially gives you one default fund rather than a broader treasury options like Mercury allows for. Which also makes sense, because unlike Mercury, Brex is less of a banking solution, so this it more bolted on functionality just to check the box in this area, versus innovating on the experience.

Brex can move money, but the whole experience feels like banking was added as an afterthought.

Yes, you can send and receive ACH, wires, and checks. You can onboard vendors through a secure link, collect W-9s, upload invoices into bill pay, and add approval flows. So on paper, there's a decent amount of functionality.

The problem is that once you actually start using it, the whole thing feels bolted on. To us, it feels much more like an expense management platform that added banking later, rather than a banking product that was built from the ground up to make transferring funds seamless. Even the way Brex frames it as a "cash management account" instead of a bank account kinda gives that away.

While Brex has native invoices, payment links, ACH/wire payments, and even ACH direct debit, it just feels unpolished an unintuitive. Compared to Mercury, it just feels old.

Not to mention, if you're using one of the newer AI accounting tools, the limitations become even more obvious. For us, that was a complete deal breaker. We use Kick, and it integrates directly with Ramp (virtual cards) and Mercury (banking), but not Brex. So unless you're cool with not exploring the world of AI accounting tools, I'd say you're better off skipping Brex.

Brex is more focused on finance‑team‑heavy companies rather than small teams.

Brex actually goes very far on the "many accounts" front: if you're approved for a Brex business account (you need a $50k bank minimum, or $1 million in revenue), you can create up to 240 separate checking accounts under one EIN, each with its own account and routing number so you can separate cash for things like payables, receivables, payroll, and tax.

But you don't get a card for each account like you would with a bank. Since Brex is an expense management software, you just spend on cards and they are all tied to one "entity" where payments come from.

Admins can set "auto‑transfer rules" per checking account, like "always keep this account at $100K" but you are unable to set auto-transfer rules like "every time money lands, automatically slice 30% tax, 20% for payroll, etc to different buckets."

All of your Brex business accounts banking (checking, treasury, vault) are tied to a single primary legal entity, and deposits must be in that primary entity's name.

If you want a completely separate Brex business account for another legal entity, you have to apply again and run it as a separate account, rather than just adding another full banking "workspace" under one login the way Mercury and Ramp allow for multiple entities.

There is no Brex personal banking solution so you can't manage your personal finances under one login (we are obsessed with Mercury Personal Banking, which is why we use Mercury for both business + personal).

Brex is very strong on roles and permissions: you get Account admins (full banking + payments), Card admins, Finance admins, plus more limited roles like Employee, Reimbursement‑only, and Auditor, and on top of that you can create granular custom roles that decide exactly who can "manage accounts & payments" versus just view data.

For each Brex checking account, you can toggle on payment approvals, set a minimum amount that requires approval, and choose one or more users who must approve any outbound payment or transfer above that threshold.

There's a lot of functionality, but it still feels more pieced together than purpose-built.

Brex's interface is fine, but the banking UX just doesn't feel like the main product.

It's relatively modern, and you can usually get to what you need without fighting with it, but once you're actually trying to do banking things, it feels like you're navigating a platform that was built for spend/expense management first, with banking being added in as an afterthought.

The biggest friction is that your cash experience is split across checking, treasury, and vault, so even simple questions like "where's our money?" can require some digging. And while search generally helps, it doesn't fix the constant underlying feeling that the banking interface is more of a secondary layer.

All-in-all, it just doesn't feel like a bank that obsessed over making money movement and visibility of your cash super easy, unlike dedicated banking apps like Mercury.