Inside 20 October: what the firm files itself and what it reminds its clients

In July we published the 2026 tax calendar: the map of the year, which forms apply depending on how the firm is set up, and the warning that the direct-debit cut-off comes before the filing deadline. That piece was the map. This one is the ground: a specific date, Tuesday 20 October 2026, and what happens inside the firm in the eight days before it.

We are writing on Monday the 12th, a national holiday in Spain. That has a practical consequence: the working week starts tomorrow, Tuesday, and the date that really matters is not the 20th but Thursday the 15th.

What falls due on 20 October

According to the AEAT taxpayer calendar, the following are filed by 20 October for the third quarter (or for September, for monthly filers):

• 303, quarterly VAT return.
• 111, withholdings on employment and professional income.
• 115, withholdings on urban property rentals.
• 130, personal income tax instalment for self-employed people under direct assessment.
• 131, the instalment under the flat-rate “módulos” scheme. In a law firm, practically never.
• 202, the second corporate income tax instalment.
• 349, the recapitulative statement of intra-EU transactions, if the firm has business clients in other Member States.

And the line that prevents the most grief: for all of these, when there is an amount to pay, direct debit is only accepted from 1 to 15 October. From Friday the 16th, whoever wants to pay has to obtain an NRC payment reference from their bank or use another payment route — which means someone with signing authority has to be around that week.

A reminder for lawyers used to civil procedure: there is no grace day here. Article 135 of the Civil Procedure Act (LEC) applies to court filings, not to tax self-assessments. The 20th ends on the 20th.

The 130 many lawyers don’t file — and the one some should

Form 130 causes more doubt in a law firm than in almost any other business, because of a rule specific to professionals. Article 109.2 of the Personal Income Tax Regulation exempts from the instalment any professional who, in the previous calendar year, had at least 70% of their activity income subject to withholding or payment on account. The form’s own instructions say it plainly: whoever meets the condition does not have to file or pay anything.

A lawyer who bills almost everything to companies, which withhold 15% (7% in the first year of activity and the two following, art. 95.1 of the Regulation), has no 130. The trouble is the lawyer with a mixed client base: family law, immigration, probate. Private individuals don’t withhold, and the percentage drops without anyone noticing.

A realistic case. Laura, a self-employed lawyer in Málaga, closed 2025 with 60% of her income subject to withholding. She is under 70%, so in 2026 she files the 130. Her cumulative figures to 30 September:

• Income: €72,000, of which €28,800 billed to companies with withholding.
• Deductible expenses: €18,000. Cumulative net income: €54,000.
• 20% of net income: €10,800.
• Withholdings suffered during the year: 15% of €28,800 = €4,320.
• Instalments paid in Q1 and Q2: €4,320.

Her Q3 form 130: 10,800 − 4,320 − 4,320 = €2,160. If she wants to pay by direct debit, she has until Thursday.

The calculation is cumulative from 1 January, which is why it cannot be done properly with the quarter in isolation: you need all three quarters’ billing and the whole year’s withholdings, reconciled.

October’s 202 now looks at 2025

For a firm incorporated as a company, October’s form 202 has a particular feature. Under the general method in article 40.2 of the Corporate Income Tax Act, the instalment is 18% of the gross tax liability (less deductions, allowances and withholdings) of the last period whose filing deadline had passed by 1 October. For a company with a calendar-year financial year, that period is 2025, whose form 200 was filed in July. In April it was based on 2024.

If the company declared a gross liability of €15,000 in July with no deductions, October’s instalment is €2,700, even if April’s was different. Companies with turnover above €6 million use the article 40.3 method and must file even when nothing is due; for everyone else, if nothing is payable, there is no 202 to file.

One week out: Tuesday the 13th

This is the day to close the numbers, not to file.

• Quarter’s billing closed. Every fee note for July, August and September issued, including those left in draft while waiting for a retainer. If the firm takes retainers, check which ones were collected and which were applied to invoices in the quarter. A retainer that was really an advance on fees and never got invoiced is the classic hole in a 303.
• Withholdings suffered reconciled. For the 130, each invoice to a company with its withholding; for the 111, every payslip and every invoice from a collaborating lawyer, expert or court agent (procurador) with withholding.
• Figures sent to the accountant, if they are the ones filing. With a reply deadline: Wednesday the 14th.
• Payment decision: direct debit (closes Thursday the 15th) or pay with an NRC before the 20th.

Client reminders go out the same Tuesday. Templates below.

The day before: Monday the 19th

If you paid by direct debit, Monday is only about checking there is money in the account and that Thursday’s filing receipts are saved. If not, Monday is for reviewing drafts with final figures and having the NRC ready. The internal rule we recommend: nothing gets filed on the 20th that wasn’t reconciled on the 19th.

The day itself: Tuesday the 20th

File whatever is left, save the PDF receipt in the quarter’s tax folder, and do one last check: the 303s and 130s of clients for whom the firm provides this service, filed one by one. The quarter is closed when the last receipt is saved, not when the last form is sent.

What the firm reminds its clients

Many firms have clients — self-employed people, companies, business tenants — who rely on being reminded. A useful reminder doesn’t say “don’t forget the 20th”: it says what is missing, by when, and what happens if it doesn’t arrive. Three short templates, written for email or WhatsApp (shown in English here; send them in the client’s language):

Self-employed client with 303 and 130:

Hi Andrés. We’re closing the third quarter: your 303 and 130 are due on Tuesday the 20th. To pay by direct debit we need your expense invoices for July to September by Wednesday the 14th at midday; direct debit closes on Thursday the 15th. If they arrive later, you’ll have to pay yourself with an NRC before the 20th.

Company with a 202:

Good morning. The second corporate income tax instalment (form 202) is due on 20 October and, in your case, is calculated on the 2025 tax we filed in July. Expected amount: €2,700. We’ll set it up for direct debit from your usual account on Thursday the 15th unless you tell us otherwise by Wednesday.

Business tenant with a 115:

Hi Marta. A reminder about form 115: the withholdings on the office rent for July to September must be paid by 20 October. Please confirm that the landlord’s three invoices show the withholding and the same amounts as last quarter; if the rent was updated, send us the new figure by Wednesday the 14th.

Three things they share: a client deadline before the direct-debit cut-off, an explicit consequence if it slips, and the amount when it is known. A reminder like this is set up once and repeated every quarter.

How Mandato helps

In Mandato, each of these milestones can live in the firm’s calendar as a recurring task with an owner: Tuesday’s data close, Thursday’s direct debit, the filing on the 20th. Client reminders go out from the same communications inbox, by email or WhatsApp, and stay on each client’s record. And if billing is already tidy at the source — as we explain in automating your firm’s billing — the quarter’s figures are ready before the accountant asks for them.

The tax authority sets the quarter’s deadline. This October, the firm’s deadline is Thursday the 15th.