What is sub-account?

A separate balance and trading area inside one exchange account, used to isolate strategies, keys, or funds.

Sub-accounts share the parent account's identity verification but can hold their own permissions and, on many venues, their own fee treatment. Isolation limits the damage a single compromised api key can do.

The feature is aimed at active traders and businesses, but the security argument applies to anyone who runs automated trading or shares access with anyone else.

How it works

A sub-account is a child of the verified parent account. It has its own balances, its own order history, and usually its own set of API keys. It does not have its own identity verification: the parent's kyc covers it, which is why creating one is instant and why a sub-account cannot be used to sidestep a jurisdiction restriction.

Three properties are the reason to use one.

Blast radius. An API key issued to a sub-account can only reach that sub-account's balance. A key compromised there cannot touch the rest.

Accounting separation. Each sub-account has its own transaction history, which makes per-strategy performance and per-entity bookkeeping straightforward rather than a reconstruction exercise.

Fee treatment. Many venues aggregate trading volume across sub-accounts for tier purposes while keeping the balances separate, so splitting activity does not push you into a worse fee tier. Whether a venue aggregates or not is stated on its own fee schedule and is worth confirming.

Transfers between the parent and its sub-accounts are internal ledger moves rather than blockchain transactions, so they are normally instant and free.

Example

Illustrative. You keep $10,000 on an exchange and run an automated strategy through an API key. With everything in one account, a leaked key with trading permission can churn the entire $10,000 through bad trades, and with withdrawal permission it can remove all of it. Move $1,000 into a sub-account and issue the key there instead, with withdrawal permission disabled and an IP allowlist. The same leak now reaches $1,000 and cannot withdraw any of it. The reduction in exposure is 90%, and it costs nothing but a transfer.

Why it matters when you buy

For a straightforward purchase this is unnecessary machinery. It becomes relevant if you automate, if more than one person has access, or if you need clean records for tax by strategy. The exchange pages list which venues support sub-accounts, and the verification tiers guide covers how the parent account's limits apply.

Related terms

• api key — what a sub-account contains the damage from
• api key permissions — the settings that matter most
• withdrawal whitelist — the other control on the same risk
• kyc — the verification the parent carries
• maker taker fee — the tier sub-accounts may share
• segregated accounts — a different and stronger separation

Questions

Do sub-accounts need separate verification?

No. They inherit the parent account's verification and its restrictions, which is what makes them instant to create and useless for evading eligibility rules.

Is my fee tier worse if I split volume?

On many venues, no, because trading volume is aggregated across sub-accounts for tier calculation. Confirm it on the venue's own fee schedule, since the practice is not universal.

Are transfers between sub-accounts free?

They are internal ledger entries rather than on-chain transfers, so they are normally instant and carry no network fee. See network fee.