Why unidentified deposits matter for a Mexican entity

The five usual causes in Mexican collections

Most unidentified deposits have ordinary explanations:

1. A useless concept. The payer typed "PAGO" or left the app's default text.
2. A different payer. A parent company, a director's personal account or a factoring firm paid on the customer's behalf.
3. Cash at a branch. Cash deposits often show only a branch number, no name.
4. Combined or split payments. One transfer covers three invoices, or one invoice arrives in two transfers.
5. Wrong entity. The customer paid your group's other Mexican company.

None of these is fraud. But each one becomes harder to solve every week it waits.

How the tax side makes old items costly

Mexican law, at a high level, works like this. The Federal Tax Code (Código Fiscal de la Federación) allows the SAT to presume that deposits in a taxpayer's account that do not match its accounting records are income, unless the taxpayer can prove otherwise. Banks also report cash deposits above a monthly threshold to the SAT. For individuals there is a separate concept, discrepancia fiscal, which compares spending and deposits with declared income.

The practical consequence for a company is simple: you should be able to explain every material deposit with documents. A loan from the parent, a capital contribution, a refund from a supplier or a transfer between your own accounts is not income, but you must be able to show that. Your local accountant will advise on specific cases.

Investigating a deposit step by step

Take an illustrative credit of 87,000.00 with the concept "TRANSFERENCIA" and a payer name your team does not recognise.

Step	Action	Result
1	Search open invoices for exactly 87,000.00	Two candidates, different customers
2	Search combinations of invoices per customer	One customer has 50,000 + 37,000 open
3	Look up the payer name in your customer master	Not found
4	Ask that customer's AP team	"Paid by our holding company"
5	Record payer alias and evidence	Applied to both invoices

If steps 1–4 fail, download the transfer's CEP (Banxico's electronic receipt) with the tracking key, which confirms the payer's account and bank. The CEP guide explains how.

Keeping a log your auditors can follow

For each open item, record date, amount, description as printed, who is investigating, what was tried and the outcome. Keep it with the month's close file. A short, dated log turns an audit question into a five-minute answer.

Date	Amount (MXN)	Description	Status	Next step
03 Oct	12,000.00	DEPOSITO EFECTIVO SUC 0218	Open	Ask branch-area customers
09 Oct	87,000.00	TRANSFERENCIA	Resolved	Holding company paid

Deposits that are legitimate but look like sales

Separate these early so they never sit in the unidentified list: intercompany loans, capital injections, insurance claims, supplier refunds, interest, and transfers between your own accounts. Each should have its own supporting document, such as a loan agreement, board minute or the other account's statement.

Cutting the volume at the source

The cheapest unidentified deposit is the one that never happens. Give every customer a reference and tell them where to type it, offer dedicated account numbers where your bank supports them, and print the payment instructions on every invoice. The options are compared in payment references in Mexico.

Where Meses fits in the investigation

Meses (meses.ai) can shorten the first steps of this search. Meses reads your bank statement PDF and your records in Google Sheets, Excel or CSV; AI proposes which customer and period each deposit belongs to, your team reviews the proposals, and Meses writes approved payments back to your sheet, with undo. Its results include matched payments, a list of payments to review and a change plan for your sheet. AI proposes and people decide: nothing is written to your sheet until your team reviews and approves the changes. The payments left for review are a natural starting point for your log of open items.