Fiat On and Off Ramps for Brokers and Desks

Ramps in brief

Liquid Mercury, the Chicago-based institutional digital asset infrastructure provider, builds trading, ledger and settlement software for desks and brokers. It is not a bank and this page does not describe a banking product. It explains the options a broker or desk has when it needs fiat in and out of its platform, and the questions to put to any provider. Treat it as a planning guide, not legal or banking advice.

Buyers in this area describe the need in plain terms: on and off ramps with fiat currencies, and accounts that let their own clients buy and sell assets such as USDT and USDC. Both come down to the same three jobs: receive money, match it to a client, and release or receive the asset.

Two kinds of ramp

Most search results for "fiat on ramp" describe the first kind. A desk or broker usually needs the second.

Ramp API options

A fiat on and off ramp API lets your platform start a payment, check its status and trigger the asset leg without staff handling each transfer. When you evaluate one, ask:

• Currencies and rails. Which currencies, and which payment rails for each (domestic transfer, wire, instant payments)?
• Direction. Is off ramp supported as fully as on ramp?
• Limits. What are the per-transaction and daily limits, and who sets them?
• Settlement timing. When does the cash count as received, and when can you release the asset?
• Reconciliation. Does the provider return references that match a payment to a client trade, and can you export them?
• Compliance split. Who runs KYC and transaction monitoring, and who is the regulated party? In the EU, ESMA's MiCA pages set out the framework, and in the UK the FCA explains the anti-money laundering regime for cryptoassets.
• Failure handling. What happens when a payment returns, is delayed, or arrives from the wrong party?

Virtual accounts

A note on search intent first. "Virtual accounts" is mostly a banking term, and many people searching for it want virtual bank accounts for consumers or businesses, not crypto infrastructure. This section is for brokers and desks. It is not a guide to opening a bank account.

In this context, a virtual account is a unique account number or payment reference that a bank or payment provider assigns to each client, usually linked to a single pooled account in your name. When a client sends money to their virtual account, the provider tells your system which client paid. Your platform can then credit that client's balance and let them trade.

Why brokers and desks use them:

• Automatic matching. Each incoming payment is tied to a client without manual lookup.
• Cleaner reconciliation. Statements show which client paid, which shortens end-of-day checks.
• Client-facing experience. Clients see an account in their own name or your brand to fund and withdraw.
• Support for stablecoin buy and sell. A client can fund a virtual account in fiat and buy a stablecoin such as USDT or USDC, or sell one and withdraw cash. For the stablecoin side, see stablecoin settlement for institutions and the stablecoin glossary entry.

What to ask a provider: who holds the pooled funds, how client money is segregated, what happens if the provider fails, which currencies are available, and which regulator supervises each party. The EBA explains how the EU treats e-money tokens, which matters if the stablecoin leg is euro-denominated.

Where ramps fit in the trade flow

A fiat ramp is one leg of a larger flow. A typical broker or OTC trade runs like this.

1. The client is onboarded and approved, with KYC and limits set.
2. The client funds their account through a ramp or virtual account.
3. The client requests a quote by RFQ or takes a streamed price.
4. The platform checks the trade against limits and executes it.
5. The asset leg settles through custody or the desk's ledger, and the cash leg is released or credited.
6. The client withdraws, or holds, in fiat or in a digital asset.

Fiat is often the slowest part of this chain, so a desk's real settlement time depends on its banking partners. Prefunding is one way to manage the exposure while cash is in transit. The wider risk picture is in counterparty risk in digital asset OTC trading, and the custody choices are in crypto custody solutions.

Mercury OTC is software for running the desk side of this flow: quoting, a ledger, risk checks and reporting, with multi-currency settlement and custody integration. K33, a crypto broker regulated by the Norwegian Financial Supervisory Authority, used Mercury OTC to automate its RFQ desk across 200 trading pairs and 8 fiat currencies, and its OTC trading volume grew 5x. See the K33 case study. Which currencies, rails and jurisdictions a new customer can use is confirmed with the Liquid Mercury team.

If you are still deciding how to set up the desk, read how to start a crypto OTC desk.

The trade itself, from quote to settlement instruction, runs in the desk's OTC platform. See Mercury OTC for how Liquid Mercury handles that workflow.

Common failure points

Most ramp problems show up in operations rather than in the technology. Plan for them before launch.

• Unmatched payments. A client sends money without the right reference, or from an account in someone else's name. Decide in advance whether you hold, return or investigate, and who decides.
• Returned payments. A transfer can be reversed after you have released the asset. Prefunding, holding periods and per-client limits manage that exposure.
• Cut-off times and weekends. Crypto markets run around the clock, but most bank rails do not. A desk that quotes at any hour still waits for banking hours to move cash on some rails.
• Currency conversion. Triangulating between currencies adds a pricing step and a second leg of risk. Make sure the desk's pricing engine and the ramp agree on rates and timing.
• Name and ownership checks. Regulators and banks expect payments to come from accounts held by the verified client. Build that check into onboarding rather than into support tickets.
• Reconciliation gaps. If the bank's records and the platform's ledger disagree, someone has to find out why each morning. Automated matching and clear references shrink that daily task.

Questions to ask any ramp provider

• Which fiat currencies and payment rails do you support, in which countries?
• Do you support both directions at the same limits?
• Who holds client funds, and how are they protected?
• Who performs KYC and monitoring, and what do you pass back to me?
• What does a reconciliation file look like, and how often do I get one?
• What are your fees and minimums, and which are fixed versus variable?
• What happens on a returned or disputed payment?