For Professional Investors only Eligibility

Institutional crypto liquidity for UK professional investor clients.

Access deep order books from 15+ managed crypto and liquidity providers through one account and one integration — with the settlement, fiat rails and APIs to run every trade.

Apply for an account Talk to the VIP desk

For investment professionals and qualifying businesses. Not available to non-professional investors, retail consumers or to individuals acting outside a trade, business or profession.

$100B+

Trading volume1

1,000+

Institutional clients

300+

Assets across 60+ networks

13 years

Operating since 2013

LIQUIDITY

Aggregated crypto liquidity, built for institutional size

One order, split across multiple order books, filled at one volume-weighted price.

THE PROBLEM

A large order walks down one venue's book. Each slice fills 
worse than the last, and your average drifts from the price 
you saw on screen.

THE MECHANISM

A crypto liquidity aggregator consolidates the order books of multiple providers into one. Prime splits your order across them, and each slice fills at the best available price2 on its venue. Prime routes aggregated order-book orders across connected liquidity providers, without taking the other side of those routed trades.

01ORDER 02CEX.IO PRIME 03AGGREGATED BOOK 04RESULT BUY BTC / USDT AMOUNT$1,000,000 ORDER TYPEMarket via FIX 4.4 · REST · WebSocket · Prime UI Validation01 Smart order router02 Order slicing03 15+ managed cryptoand liquidity providers One consolidated fillone volume-weighted price Prime Walletone internal ledger
01ORDER BUY BTC / USDT AMOUNT$1,000,000 ORDER TYPEMarket via FIX 4.4 · REST · WebSocket · Prime UI 02CEX.IO PRIME Validation01 Smart order router02 Order slicing03 03AGGREGATED BOOK 15+ managed cryptoand liquidity providers 04RESULT One consolidated fillone volume-weighted price Prime Walletone internal ledger
How an order fills on CEX.IO Prime
slice filled at the best available price available depth

Execution quality, measured.3

EFFECTIVE SPREAD

3–8 bps

vs ~18 bps on a single venue

CEX.IO Prime 3 to 8 basis points, single venue about 18

SLIPPAGE ON $1M BTC-USDT

~5 bps

vs ~12 bps on a single venue

CEX.IO Prime about 5 basis points, single venue about 12

FILL RATE AT SIZE

97%

vs ~78% on a single venue

CEX.IO Prime 97 percent, single venue about 78 percent

▬ CEX.IO Prime, aggregated     ▬ Single venue, top of book

OPERATING COST

The hidden cost of multi-venue crypto trading

Depth is only half of what trading across several exchanges costs. The rest is counterparty risk, repeated onboarding, fragmented controls and idle capital. Prime consolidates all four into one relationship.

01

Counterparty risk on every exchange

Every exchange you trade on holds part of your balance and is another counterparty to assess, monitor and re-approve. With Prime, execution and settlement are accessed through one integrated account relationship and interface.

02

KYB and onboarding, venue by venue

Each exchange brings its own KYB, legal review and compliance perimeter — then its own renewal cycle. One Prime onboarding process provides access to eligible aggregated liquidity, supported fiat payment functionality and sub-accounts.

03

Fragmented API keys, approvals and statements

Five sets of API keys, five approval models, five statements to reconcile. Prime books every execution to one internal ledger, with role-based access and a single audit log.

04

Pre-funding and rebalancing costs

Pre-funding each exchange leaves capital idle, while rebalancing may involve transfer fees and time out of the market. On Prime your funds stay on one account and do not leave it at the moment of execution.

EXECUTION

Four ways to execute: order book, Instant Convert, RFQ and OTC

Pick the mechanism that fits the trade. All four settle to the same account, the same ledger and the same report.

Order Book

Self-service

Aggregated order book with limit and market orders against aggregated liquidity.

BEST FOR
Active trading, and control over order type and price

Instant Convert

Self-service

Conversion at a fixed price, valid for a short window.

BEST FOR
Fast, predictable conversions

RFQ

Self-service

Request-for-quote for an individually priced trade.

BEST FOR
Larger or less-liquid trades where you want the price before committing

OTC Execution

High-touch

Assisted, off-book execution agreed with your relationship manager.

BEST FOR
Larger spot transactions or transactions requiring negotiated execution

PRODUCTS

Institutional settlement, accounts and wallet infrastructure around every trade

Liquidity is the product. This is the infrastructure that supports it.

One account, sub-accounts underneath

Fiat and crypto in one account view. Sub-accounts per business line, client group or strategy — each with its own deposit addresses, history and controls, and API keys scopable to one of them.

One account, sub-accounts underneath

Prime Liquidity

Aggregated liquidity on one account, reachable four ways: order book, Instant Convert, RFQ and assisted OTC execution.

Asset security

CEX.IO provides secure account and wallet infrastructure for client asset management, with withdrawals subject to whitelisting address requirements and configurable approval controls.

Governance & controls

Role-based access. Single, dual or threshold approvals you configure yourself. Full audit log of who initiated, who approved, how and when. SSO and 2FA.

Settlement & payments

Faster Payments, SEPA, SEPA Instant, SWIFT and wires through a regulated payment partner. Multi-currency balances in GBP, EUR and USD. Near-instant settlement on rails that support it. Stablecoin settlement across popular networks.4

Professional onboarding

KYB and CEX.IO's Professional Investor appropriateness test before access. Products, limits and controls are then set with your relationship manager.

Platform access

The Prime terminal for your traders, FIX 4.4 for your order management system, REST and WebSocket for your platform, Webhooks for your back office. Same account, same balances, same controls.

Reporting

One internal ledger behind every product. Statements at account and sub-account level, plus per-product reporting correlated by order, transaction and your own reference IDs.

Dedicated relationship manager

A named relationship manager for your account, backed by a 24/7 institutional desk. Onboarding, limits, controls and product scope are set with you, then reviewed as your flow changes.

WHO IT'S FOR

Built for UK professional trading businesses

Prime is configured for each eligible client at onboarding, once Professional Investor status is confirmed. These are the shapes it most often takes.

Payment institutions & EMIs

Convert eligible fiat balances into supported crypto-assets or stablecoins through Prime, with access to supported SEPA Instant, Faster Payments and SWIFT, where available.

Execution and same-day fiat from one provider

Exchanges & approved brokers

Access aggregated liquidity for trading activity through one integration, without maintaining separate venue relationships and accounts for each connected venue.

Aggregated depth through one integration

Payment providers & wallets

Integrate eligible liquidity, conversion and settlement functionality into approved institutional workflows through APIs and Webhooks. The permissions your own services require remain your responsibility.

Crypto and fiat connectivity through one integration

OTC desks

Use RFQ for price certainty on larger spot transactions, or order slicing across available venues to manage market impact, with assisted OTC spot execution where available.

Price certainty and execution flexibility for larger spot trades

Asset managers & funds

Spot execution on aggregated depth, with a sub-account per fund or mandate and reporting correlated to your own reference IDs.

Sub-accounts per fund or mandate

Trading firms & treasuries

Access aggregated spot liquidity, stablecoin conversion and client-directed treasury rebalancing through configurable account and approval controls.

Spot execution and treasury controls

Eligibility in the UK

Professional investor clients only

Eligibility is assessed at onboarding, alongside KYB and CEX.IO's Professional Investor appropriateness test. We may decline any application.

Who can apply

  • Firms authorised or regulated by the FCA or another financial regulator
  • Businesses whose ordinary activities involve trading or investing in cryptoassets or other investments
  • Companies, partnerships and trusts that meet the high net worth company thresholds in Article 49 of the Financial Promotion Order
  • In every case, applicants who have passed CEX.IO's Professional Investor appropriateness test

Not available to

  • Retail consumers and non-professional investors
  • High net worth or sophisticated individuals
  • Individuals acting outside a trade, business or profession
  • Applicants that do not complete KYB or the Professional Investor appropriateness test

Something else? Tell us your model — products, assets, rails, limits and controls are set to fit it at onboarding. Talk to our team

CONNECT

Crypto liquidity API — FIX 4.4, REST and WebSocket

Order entry, market data and account events over the transports your stack already speaks.

  • FIX 4.4session-based order entry and execution reporting
  • RESTorders, balances, history, rates, trading conditions
  • WebSocketstreaming market data, order and account events
  • Webhooksevents pushed to your endpoint, no polling
  • Sandboxvalidate your integration before you go live
POST /api/rest/new_orderhttp
POST https://liquidity.prime.cex.io/api/rest/new_order
X-AGGR-KEY:        <your-api-key>
X-AGGR-TIMESTAMP:  1758470400
X-AGGR-SIGNATURE:  <hmac-sha256>
Content-Type:      application/json

{ "pair": "BTC-USDT", "side": "buy", "type": "market",
  "amount": "1000000", "clientOrderId": "your-ref-001" }

■   99.99% uptime   ·   Full API reference at docs.prime.cex.io

REGULATION

Regulatory status in the UK

Factual information on our UK registration: what it covers, and what it does not.

UNITED KINGDOM

FCA-registered cryptoasset business

CEX.IO Markets UK Ltd, FRN 1007192. Registered under the Money Laundering Regulations 2017.

WHAT REGISTRATION MEANS

Registration relates to anti-money-laundering and counter-terrorist financing supervision. It does not constitute authorisation, approval or endorsement by the FCA.

The Financial Services Compensation Scheme and the Financial Ombudsman Service do not apply to cryptoasset activities.

CEX.IO GROUP

Licensed money transmitter in the majority of US states

CEX.IO Corp. · US Licenses and Registrations

FinCEN MSB registration

CEX.IO Corp.

Held by group entities outside the UK. They do not extend any protection to UK clients.

Security & resilience5
  • PCI DSS Level 1 certified
  • Controls mapped to SOC 2 Trust Services Criteria
  • ISO 27001-aligned information security management
  • Travel Rule data exchange for crypto transfers

COMPARISON

Why professional investors choose CEX.IO Prime

The edge is the combination — not any single row.

Capability CEX.IO Prime Pure-play liquidity provider Crypto exchange Software EMS
Multi-venue aggregation across CEX and DEX full not offered not offered full
Integrated real-time fiat rails (Faster Payments / SEPA Instant / SWIFT)4 full partial partial not offered
One account relationship for execution and settlement full partial not offered not offered
Conflict-free: no proprietary book trading against your flow full not offered partial full
full partial not offered

CEX.IO Prime

Multi-venue aggregation across CEX and DEX
full
Integrated real-time fiat rails (Faster Payments / SEPA Instant / SWIFT)4
full
One account relationship for execution and settlement
full
Conflict-free execution
full

Pure-play liquidity provider

Multi-venue aggregation across CEX and DEX
not offered
Integrated real-time fiat rails (Faster Payments / SEPA Instant / SWIFT)4
partial
One account relationship for execution and settlement
partial
Conflict-free execution
not offered

Crypto exchange

Multi-venue aggregation across CEX and DEX
not offered
Integrated real-time fiat rails (Faster Payments / SEPA Instant / SWIFT)4
partial
One account relationship for execution and settlement
not offered
Conflict-free execution
partial

Software EMS

Multi-venue aggregation across CEX and DEX
full
Integrated real-time fiat rails (Faster Payments / SEPA Instant / SWIFT)4
not offered
One account relationship for execution and settlement
not offered
Conflict-free execution
full

FAQ

Frequently asked questions

No. In the UK, CEX.IO Prime is for professional investors only: investment professionals and qualifying businesses that pass CEX.IO's Professional Investor appropriateness test. It is not available to non-professional investors, retail consumers or individuals acting outside a trade, business or profession.

CEX.IO Markets UK Ltd (FRN 1007192) is registered with the FCA as a cryptoasset business under the Money Laundering Regulations 2017. Registration relates to anti-money-laundering and counter-terrorist financing supervision. It does not constitute authorisation, approval or endorsement by the FCA.

No. Cryptoasset activities are not covered by the Financial Services Compensation Scheme, and complaints about them cannot be referred to the Financial Ombudsman Service. Asset protection terms are set out in your client agreement.

A crypto liquidity aggregator consolidates the order books of many trading venues into one book, then routes each order to the best available prices across those venues, as determined by the routing logic. Instead of executing against the depth of a single venue, your order draws on combined depth — while you still manage one order, one account and one report.

Prime is not a single-venue liquidity provider. It connects to a liquidity aggregator that combines 15+ managed crypto and liquidity providers, centralised and decentralised, into a single aggregated order book. The composition is managed by the aggregator and changes as markets do.

No. Prime routes your order to the market; it does not take the other side of it, and it does not match orders between Prime clients.

Client assets are held on CEX.IO's in-house infrastructure. Withdrawals go only to whitelisted addresses, under approval rules you configure. Legal entity and asset protection terms are set out in your client agreement.

Client funds do not leave Prime at the moment of execution. Your balance updates immediately on Prime's internal ledger; settlement between Prime and the aggregator runs as a periodic background process, not per trade.

GBP, EUR and USD over Faster Payments, SEPA, SEPA Instant, SWIFT and wires through a regulated payment partner, with near-instant settlement on rails that support it.4 Crypto settlement covers 300+ assets across 60+ blockchain networks.

Prime is a spot platform. It does not offer derivatives, leverage or loans. Execution covers order book trading, Instant Convert, RFQ and assisted OTC execution.

Through the Prime UI, or programmatically over FIX 4.4, REST and WebSocket, with Webhooks for event delivery. A sandbox is available for integration testing before going live.

Commission is set per client and reflects your trading profile and volume.

Onboarding starts with KYB: your company's jurisdiction of establishment, ownership and business activity, followed by CEX.IO's Professional Investor appropriateness test. Once approved, products, limits and controls are set with your relationship manager, and you get access to the Prime terminal and APIs, with a sandbox for integration testing before going live.

Your contracting entity is confirmed during onboarding. The group's UK entity is CEX.IO Markets UK Ltd, registered in England and Wales (company number 15140258). Detailed conditions are set out in the Terms of Use.

GET STARTED

Apply for an account, or start with a conversation

Tell us how you trade and how you settle. We confirm Professional Investor status, then come back with the products, the limits and the contracting entity that apply to you.

Prefer self-service?

Onboarding with KYB and the Professional Investor appropriateness test, then platform access — fund the account and trade aggregated liquidity yourself.

Apply for an account

Already a client? Log in

Notes

  1. Scale figures. $100B+ trading volume and 1,000+ institutional clients are aggregated CEX.IO Group figures across all group entities and products, as of 2025–2026. Trading volume means total executed volume across CEX.IO Group platforms over the last 24 months.
  2. Best available price means the best executable price identified by the routing logic among connected eligible venues at the time of execution, subject to available depth, fees, latency, market conditions, client limits and execution constraints. It is not a guarantee of the best price across the entire market: venues not connected to Prime may offer better pricing.
  3. Execution metrics. Based on CEX.IO Prime internal execution data for Q1 2026, BTC-USDT, representative $1M market orders, compared against top-of-book execution on a single venue. Fees excluded. Actual spreads, slippage, fill rates and execution outcomes vary with market conditions, liquidity, latency, order characteristics and venue availability; historical data is not a guarantee of future results.
  4. Fiat payments. Fiat payment functionality is subject to jurisdiction and eligibility and may be provided through authorised banking or payment-service partners.
  5. Security frameworks. Alignment statements reflect CEX.IO's internal assessment of its controls against these frameworks. They do not represent a SOC 2 report or an ISO 27001 certification.