Sub-account

What it means

The chart of accounts has control accounts - 311 Trade receivables, 518 Other services, 221 Bank accounts. A sub-account is a finer split of those: 311.001 for one customer, 518.010 for marketing, 518.020 for legal fees, 221.EUR and 221.CZK for two bank accounts.

The account number gets longer, but the statements do not change: in the general ledger and in the annual closing the sub-accounts roll back up into the control account. You get the detail without breaking the reporting structure.

Control accounts are prescribed by the framework chart of accounts; sub-accounts the company creates itself and records in its own account plan. The rules do not say which sub-accounts you must have, but they do require the plan to be documented and the sub-accounts to agree with the control account balance at any moment.

How it works in practice

Sub-accounts are the cheapest way to get reporting out of the books themselves instead of a spreadsheet beside them. Cost by site, revenue by country, projects, webshop channels - all of it can be read off the trial balance when the breakdown is set up in advance.

When we take over the books we ask what you want to follow during the year and design the sub-accounts around that. They can be added mid-year, but comparability with earlier months suffers.

In Slovak practice sub-accounts also serve tax purposes. One control account, say fines and penalties or other operating costs, is split into a deductible and a non-deductible sub-account, and the amount to be added back in the return as a non-deductible expense is then read straight from the books. Without that split it is hunted down in the documents by hand, usually in a rush before the deadline.

What to watch out for

The opposite extreme is the real risk: a sub-account for every trifle. Hundreds of accounts nobody reads, more posting work and more posting errors. A good breakdown has as many levels as there are decisions taken from it, and not one more.

The second mistake is sub-accounts without rules. If nobody has written down what belongs where, the same kind of cost lands on marketing one month and on IT the next, depending on who posted it. The report then shows swings that do not exist. The mapping belongs in an internal policy or at least in a shared list that everyone who posts entries uses.