Save Losses And Claims

PUT /tenants/{tenant}/clients/{client}/mtd/losses/document/{businessId}/{taxYear}

Sends one income source's whole losses-and-claims position for a tax year from 2026-27 onwards. A full replacement of what HMRC hold — anything omitted is cleared — so the request must carry every figure that should survive. HMRC accept it only after the tax year has ended, and carry-back claims must be sent before the tax return is filed.

Parameters

Name	Type	Description
tenant*	path string	The Tenant.Code
The Tenant.Code
client*	path string
businessId*	path string
taxYear*	path string

Request Body*

SaveMtdLossesAndClaimsRequest

{
  "claims": {
    "carryBack": "...",
    "carrySideways": "...",
    "preferenceOrder": "...",
    "carryForward": "..."
  },
  "losses": {
    "broughtForwardLosses": 0
  }
}

Responses

200 OK

MtdSubmissionReceiptDto

400 Bad Request

401 Unauthorized – Invalid or missing API key

404 Not Found