Making Tax Digital for Income Tax Hit STL Owners in April 2026: What the First Quarter Actually Required
By STL Accounting and Finance
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In short: MTD for Income Tax Self Assessment began phased introduction from April 2026. Individual STL owners with combined self-employment and property income above the qualifying threshold are now required to keep digital records and submit quarterly updates. Six months in, the compliance is more work than most operators expected - and the software choices matter more than the marketing suggests.
Making Tax Digital for Income Tax Self Assessment (MTD ITSA) is not a new announcement - it has been trailed and delayed and re-scoped for the better part of a decade. What is new, from April 2026, is that it is actually running. Individual STL owners with combined self-employment and property income over the qualifying threshold (currently £50,000, dropping over the phased introduction) are now required to keep digital records and submit quarterly updates to HMRC.
This piece is not a policy primer - HMRC publishes those. This is what the compliance has actually looked like across our client base since April.
What the quarterly submission actually contains
Each quarterly update is a summary of income and allowable expenses for the quarter, submitted to HMRC through MTD-compatible software. The submission is a running total to the end of that quarter, not a final settled position. There is no tax paid on the quarterly submission - the tax calculation happens at the end-of-period statement and final declaration stage, and payment still falls on the existing self-assessment dates.
For an STL owner, the categories that matter for the quarterly return are:
- Turnover per property (booking income received in the quarter)
- Allowable expenses (cleaning, utilities, platform fees, insurance, professional fees, and so on)
- Motor expenses (where applicable)
- Mortgage interest (restricted to basic-rate credit post-FHL abolition)
The categorisation matters. HMRC's quarterly submission fields are strict about what counts as what.
Where DIY has gone wrong
We have picked up several clients through the summer who tried to run MTD themselves before deciding it was not worth the time. Common issues:
Software choice. Not all MTD-compatible software is equally good at STL income specifically. Some cloud accounting tools categorise Airbnb payouts as a single line per payout rather than per stay; others net the platform fee against the booking rather than showing gross booking + separate fee. Both produce the same taxable profit but the second is much less useful when reconciling against platform statements.
Multi-platform income reconciliation. Where a property is listed on Airbnb, Booking.com and Vrbo simultaneously, importing each platform's data cleanly - without duplicates, without missing bookings - is more work than a spreadsheet does well. Every operator who tried to run this from a spreadsheet has come to us within two quarters.
Missed quarterly deadline. The first quarterly submission for a 6 April 2026 accounting period was due 7 August 2026. Late-submission penalties are now a real thing under the new regime. Operators who missed this deadline start the year with a penalty and a compliance flag on their HMRC record.
What the quarterly cadence actually does to your business
Two operational consequences we did not see written about in the run-up but which have become obvious in practice:
Quarterly reconciliation forces earlier realisation of cash-flow issues. An operator who reconciles once a year at self-assessment time discovers the tax bill in January. An operator who reconciles quarterly under MTD sees it building through the year. This is, in the medium term, a good thing. In the short term, several of our clients have found the quarterly view surprising - specifically, the compounding effect of the post-FHL mortgage interest restriction has been more visible than they expected.
The quarterly submission creates a permanent, digital, HMRC-held record of exactly which properties produced what income in which periods. This is worth pausing on. This record is queryable by HMRC and, under existing data-sharing arrangements, discoverable by local planning authorities in principle. For an operator whose planning position is unresolved, MTD creates a more granular data trail than existed before. Our main site covers the planning implications in more detail.
What operators should do
- If you are over the threshold and not yet on MTD-compliant software, get on it. The next quarter's submission window closes soon.
- Get an accountant who understands STL income specifically. A generalist accountant will produce compliant returns, but often at the cost of missing sector-specific reliefs.
- Treat the quarterly view as management information, not just compliance. If the quarterly reconciliation is throwing up surprises, act on them - do not wait for the next quarter.
Book a free 15-minute consultation to talk through your position.
Where we come in
MTD, DAC7, HMRC nudge letters — the compliance load is now real. We carry it.
STL Accounting and Finance is the United Kingdom's only accounting practice focused exclusively on short-term let and holiday let operators. Everything in this piece — the calculations, the compliance, the reconciliations, the deadlines — is what our clients hand to us and stop worrying about.
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Bookkeeping, VAT, self-assessment, HMRC liaison, tax planning. All included.
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