Quarterly Summary Builder

The Quarterly Summary Builder aggregates your property income and expenses into the exact format required by the HMRC Making Tax Digital Income Tax Self Assessment (MTD ITSA) API. Before any data leaves the platform, you can review a structured summary and confirm that all figures are correct.

Overview

Each time a quarterly submission period opens, the platform:

1. Pulls all transactions for each property from your connected AgentOS record.
2. Groups income and expenses by property and by HMRC quarter.
3. Maps the aggregated totals to the corresponding HMRC MTD ITSA API fields.
4. Presents a pre-submission review screen so you can verify the numbers before submitting.

HMRC Quarter Periods

HMRC MTD ITSA uses four fixed quarters per tax year:

Quarter	Period
Q1	6 April – 5 July
Q2	6 July – 5 October
Q3	6 October – 5 January
Q4	6 January – 5 April

Transactions imported from AgentOS are automatically assigned to the correct quarter based on their date.

Pre-Submission Review Screen

Before submitting to HMRC, you will see a summary table that includes:

• Property address — each property on your portfolio is listed separately.
• Income total — aggregated rental income for the quarter.
• Expense totals — broken down by expense category as required by the MTD ITSA schema (e.g. premises costs, repairs and maintenance, financial costs, professional fees, other allowable property expenses).
• Net profit / loss — calculated automatically from the above.
• HMRC field reference — the specific API field each line maps to, so you can cross-check against HMRC guidance if needed.

No data is sent to HMRC until you explicitly confirm and submit from this screen.

Field Mapping to HMRC MTD ITSA API

The summary maps directly to the HMRC MTD ITSA uk-property business source adjustable summary (BSAS) schema. Key fields include:

periodIncome
  └── rentIncome
  └── premiumsOfLeaseGrant
  └── reversePremiums
  └── otherPropertyIncome

periodExpenses
  └── premisesRunningCosts
  └── repairsAndMaintenance
  └── financialCosts
  └── professionalFees
  └── costOfServices
  └── other

These fields are populated automatically from your imported AgentOS transactions. You should review category assignments to ensure each transaction has been correctly classified before submitting.

Requirements

• An active AgentOS API connection (so transactions can be imported).
• A valid National Insurance Number registered on your account (required by HMRC for MTD ITSA authentication).
• HMRC MTD ITSA authorisation completed via the OAuth flow.

Submitting After Review

1. Navigate to Submissions → Quarterly Summary.
2. Select the tax year and quarter you wish to submit.
3. Review the per-property breakdown.
4. If all figures are correct, click Submit to HMRC.
5. The platform will call the HMRC MTD ITSA API and display a confirmation reference number on success.

If you spot an error, return to Transactions to correct the relevant entry, then come back to the summary — totals update automatically.

Frequently Asked Questions

Can I edit the aggregated totals directly? No. Totals are derived from your transaction records to maintain a clear audit trail. Edit the underlying transactions and the summary will recalculate.

What if a transaction spans two quarters? Transactions are allocated to the quarter in which their date falls. If a payment covers multiple periods, split it into separate transaction entries dated appropriately.

Will submitting one property affect others? Each property is submitted independently. You can submit one property's quarterly figures without affecting any other property on your portfolio.