Self‑Assessment Integration Guide (MTD ITSA)

This guide documents the canonical field sets used for UK Self-Employment under MTD ITSA.

It covers the two tax sources used by the configurator:

• UK-ITSA-SE-QU
• UK-ITSA-SE-EOPS

These field sets are seeded by App.proc_Template_ST_SOLE_CUR_MIN_2026 and are presented in the Tax Configurator as canonical tag names.

Scope

This document covers:

• Quarterly Update fields
• Annual End-of-Period Statement fields
• adjustments
• losses
• basis period items
• capital allowances

It does not cover:

• capital introduced
• drawings
• SA100 aggregation
• property income

Capital introduced and drawings are balance-sheet movements and are handled separately.

Source codes

TaxSourceCode	Purpose	Notes
UK-ITSA-SE-QU	Quarterly Update	Totals only
UK-ITSA-SE-EOPS	End-of-Period Statement	Annual return layer with adjustments and allowances

Tag class behaviour

The configurator uses tag classes to distinguish field behaviour:

• Component tags are mappable
• Derived tags are read-only
• Rollup tags are read-only

That keeps the totals, adjustments, and final profit items separated clearly.

Deliverable A: Quarterly Update field set

These are the canonical QU fields used by UK-ITSA-SE-QU.

FieldName	Meaning
turnover	Total sales, takings, or receipts for the period
otherIncome	Other business income not included in turnover
costOfGoods	Cost of goods bought for resale or used in providing services
constructionCosts	Payments to subcontractors and other construction-related costs
wagesSalaries	Staff wages, salaries, bonuses, and employer pension contributions
carVanExpenses	Motor expenses such as fuel, repairs, insurance, and servicing
travelExpenses	Travel costs not covered by motor expenses
premisesRunningCosts	Rent, utilities, repairs, and maintenance of business premises
maintenanceCosts	General repairs and maintenance not tied to premises
adminCosts	Office and administration expenses such as postage, stationery, phone, and software
advertisingMarketing	Advertising, marketing, website, and promotion
interestOnLoans	Interest on business loans
financialCharges	Bank charges and similar financial costs
badDebts	Allowable bad debt write-offs
professionalFees	Accountancy, legal, and consultancy fees
depreciation	Depreciation shown for completeness as a derived presentation field
otherExpenses	Any allowable business expenses not covered above

Notes on the QU set

• The list is vendor-canonical but aligned to the SA103F quarterly presentation.
• depreciation is shown for completeness and should be treated as a derived presentation field rather than a cash mapping target.
• QU values are totals only.

Deliverable B: EOPS field set

Chunk 1: Accounts totals + adjustments

FieldName	Meaning	Notes
turnover	Total business income for the year	Reused from QU
otherIncome	Other business income not in turnover	Reused from QU
costOfGoods	Cost of goods bought for resale or used in services	Reused
constructionCosts	CIS subcontractor costs	Reused
wagesSalaries	Staff wages, salaries, and pensions	Reused
carVanExpenses	Motor expenses	Reused
travelExpenses	Travel costs	Reused
premisesRunningCosts	Rent, utilities, and premises repairs	Reused
maintenanceCosts	General repairs not tied to premises	Reused
adminCosts	Office and administration expenses	Reused
advertisingMarketing	Advertising, marketing, and promotion	Reused
interestOnLoans	Interest on business loans	Reused
financialCharges	Bank charges and similar costs	Reused
badDebts	Allowable bad debts	Reused
professionalFees	Accountancy, legal, and consultancy	Reused
depreciation	Depreciation charged in accounts	Disallowed later
otherExpenses	Any allowable expenses not listed	Reused
goodsForOwnUse	Value of goods taken from the business for personal use	Required for annual adjustments
disallowableCostOfGoods	Non-allowable portion of costOfGoods	Vendor-canonical
disallowableWages	Non-allowable portion of wagesSalaries	Vendor-canonical
disallowableMotor	Non-allowable portion of carVanExpenses	Vendor-canonical
disallowableTravel	Non-allowable portion of travelExpenses	Vendor-canonical
disallowablePremises	Non-allowable portion of premisesRunningCosts	Vendor-canonical
disallowableMaintenance	Non-allowable portion of maintenanceCosts	Vendor-canonical
disallowableAdmin	Non-allowable portion of adminCosts	Vendor-canonical
disallowableAdvertising	Non-allowable portion of advertisingMarketing	Vendor-canonical
disallowableInterest	Non-allowable portion of interestOnLoans	Vendor-canonical
disallowableFinancial	Non-allowable portion of financialCharges	Vendor-canonical
disallowableBadDebts	Non-allowable portion of badDebts	Vendor-canonical
disallowableProfessional	Non-allowable portion of professionalFees	Vendor-canonical
disallowableOther	Non-allowable portion of otherExpenses	Vendor-canonical
accountingProfit	Profit per accounts before adjustments	SA103F concept
totalDisallowables	Sum of all disallowable expenses	Derived
adjustedProfit	Profit after disallowables and goods for own use adjustments	Feeds losses and capital allowances

Chunk 2: Losses + basis period + overlap items

FieldName	Meaning	Notes
lossBroughtForward	Loss from earlier years brought into this year	SA103F equivalent
lossUsedAgainstProfit	Loss used to reduce this year’s adjusted profit	Vendor-canonical
lossCarriedForward	Remaining loss carried forward to future years	SA103F equivalent
lossUsedAgainstOtherIncome	Loss set against other income	Only if applicable
lossUsedAgainstCapitalGains	Loss set against capital gains	Vendor-canonical
postCessationReceipts	Receipts after the business ceased	SA103F concept
postCessationExpenses	Allowable expenses after cessation	SA103F concept
basisPeriodStart	Start date of the basis period for the tax year	Required for EOPS
basisPeriodEnd	End date of the basis period for the tax year	Required for EOPS
basisPeriodAdjustedProfit	Profit allocated to the basis period after adjustments	Feeds final tax computation
basisPeriodDisallowables	Total disallowable expenses for the basis period	Derived
overlapProfit	Overlap profit carried from earlier years	SA103F equivalent
overlapReliefUsed	Overlap relief used in the tax year	Required for basis period reform
transitionalProfit	Transitional profit arising from basis period reform	Basis period reform item
transitionalRelief	Relief applied to transitional profit	Vendor-canonical
transitionalProfitSpread	Amount of transitional profit spread over future years	5-year spreading rule
adjustedProfitForTax	Final profit after overlap relief and transitional adjustments	Feeds capital allowances and losses

Chunk 3: Capital allowances

FieldName	Meaning	Notes
capitalAllowancesClaimed	Total capital allowances claimed for the year	High-level summary
annualInvestmentAllowance	Annual Investment Allowance claimed on qualifying plant and machinery	SA103F concept
writingDownAllowanceMainPool	Writing Down Allowance for the main pool	Based on remaining pool value
writingDownAllowanceSpecialRate	Writing Down Allowance for the special rate pool	Vendor-canonical
writingDownAllowanceSingleAsset	Writing Down Allowance for single asset pools	Vendor-canonical
smallPoolsAllowance	Small pools allowance	SA103F concept
balancingChargeMainPool	Balancing charge for main pool disposals	Increases taxable profit
balancingChargeSpecialRate	Balancing charge for special rate pool disposals	Vendor-canonical
balancingChargeSingleAsset	Balancing charge for single asset pool disposals	Vendor-canonical
balancingAllowanceMainPool	Balancing allowance for main pool	Reduces taxable profit
balancingAllowanceSpecialRate	Balancing allowance for special rate pool	Vendor-canonical
balancingAllowanceSingleAsset	Balancing allowance for single asset pools	Vendor-canonical
privateUseAdjustment	Adjustment for private use of assets	Required for annual treatment
carMainRateAllowance	Allowance for cars qualifying for the main rate	CO₂-based rules
carSpecialRateAllowance	Allowance for cars qualifying for the special rate	CO₂-based rules
carBalancingCharge	Balancing charge for car disposals	Vendor-canonical
carBalancingAllowance	Balancing allowance for car disposals	Vendor-canonical
enhancedCapitalAllowance	Enhanced Capital Allowance	If applicable
superDeductionAllowance	Super-deduction allowance	Only for relevant years
fullExpensingAllowance	Full expensing allowance	Vendor-canonical
specialRateFirstYearAllowance	Special rate first-year allowance	Vendor-canonical
poolOpeningValueMainPool	Opening written-down value of the main pool	Needed for computation
poolOpeningValueSpecialRate	Opening written-down value of the special rate pool	Vendor-canonical
poolOpeningValueSingleAsset	Opening written-down value of single asset pools	Vendor-canonical
poolClosingValueMainPool	Closing written-down value of the main pool	Derived
poolClosingValueSpecialRate	Closing written-down value of the special rate pool	Derived
poolClosingValueSingleAsset	Closing written-down value of single asset pools	Derived
capitalAllowancesTotal	Sum of all allowances after private use adjustments	Feeds adjusted profit

Notes

• HMRC does not publish a formal JSON schema for EOPS, so these names are vendor-canonical.
• The EOPS set is aligned to SA103F annual semantics and basis period reform rules.
• Capital introduced and drawings are not included because they are balance-sheet movements, not tax return fields.

Implementation notes

• The configurator seeds UK-ITSA-SE-QU and UK-ITSA-SE-EOPS.
• The annual source is the place where adjustments, losses, basis period items, and capital allowances are applied.
• QU remains totals only.