HMRC letter codes · One-to-many letters
PROR2bMMLetter about a provisional Business Asset Roll-over Relief claim, later of two
Published by its source on 28 May 2024. A date in the letter that has passed stays passed: what a passed date means.
Last reviewed 14 October 2026 · How Tax Letters checks its facts
In short
HMRC's letter PROR2bMM is headed “Please check your 2021 to 2022 Business Asset Roll-over Relief claim”.
“PROR2bMM … Please check your 2021 to 2022 Business Asset Roll-over Relief claim”
ICAEW: HMRC letter PROR2bMM, as published with its tax news item · checked 14 October 2026
Information, not advice: this page reports what HMRC, GOV.UK and the bodies named publish about PROR2bMM. Each fact has its source and the day it was checked beside it.
When HMRC sends it
HMRC's letter PROR2bMM says it is written because the reader's 2021 to 2022 Self Assessment tax return included a provisional Business Asset Roll-over Relief (RoR) claim.
“PROR2bMM … We’re writing to you because your 2021 to 2022 Self Assessment tax return included a provisional Business Asset Roll-over Relief (RoR) claim.”
ICAEW: HMRC letter PROR2bMM, as published with its tax news item · checked 14 October 2026
ICAEW said, in the news item with HMRC's letter PROR2bMM, that HMRC would write later that year to taxpayers who were yet to replace a provisional claim for 2021/22 with a valid claim.
“Later in the year, … HMRC will write to taxpayers … who are yet to replace a provisional claim for 2021/22 with a valid claim.”
ICAEW: HMRC reminds taxpayers about roll-over relief claims · checked 14 October 2026
What it asks
HMRC's letter PROR2bMM asks the reader to look again at the original provisional claim for Business Asset RoR.
“PROR2bMM … Please look again at your original provisional claim for Business Asset RoR.”
ICAEW: HMRC letter PROR2bMM, as published with its tax news item · checked 14 October 2026
ICAEW says, beside HMRC's letter PROR2bMM, that a taxpayer who made a provisional claim must replace it with a valid claim once they buy the qualifying asset.
“They must replace the provisional claim with a valid claim once they buy the qualifying asset.”
ICAEW: HMRC reminds taxpayers about roll-over relief claims · checked 14 October 2026
Free help and HMRC contacts
HMRC's letter PROR2bMM points to GOV.UK, search “HS290”, for more information about claiming Business Asset RoR.
“PROR2bMM … If you need more information about claiming Business Asset RoR, go to GOV.UK and search 'HS290'.”
ICAEW: HMRC letter PROR2bMM, as published with its tax news item · checked 14 October 2026
HMRC's letter PROR2bMM points to GOV.UK, search “Self Assessment tax return”, for help to fill in a tax return correctly.
“PROR2bMM … If you need help to fill in your tax return correctly, go to GOV.UK and search 'Self Assessment tax return'.”
ICAEW: HMRC letter PROR2bMM, as published with its tax news item · checked 14 October 2026
Free help first
These routes are described by GOV.UK, TaxAid and Citizens Advice themselves.
- HMRC's extra supportHMRC offers extra support if your health condition or personal circumstances make it difficult to contact HMRC, for example a mental health condition, financial hardship or being treated in hospital.
- Someone to deal with HMRC for youYou can authorise a friend, relative or voluntary organisation to talk to HMRC for you and help you fill in forms.
- TaxAidTaxAid helps people with tax problems who cannot pay for advice. Tax Help for Older People merged with TaxAid in July 2025.
- Citizens AdviceCitizens Advice gives confidential advice online, over the phone and in person, for free.
- ICAEW: HMRC letter PROR2bMM, as published with its tax news item (checked 14 Oct 2026)
- ICAEW: HMRC reminds taxpayers about roll-over relief claims (checked 14 Oct 2026)
- GOV.UK: Get help from HMRC if you need extra support (checked 7 Oct 2026)
- GOV.UK: Appoint someone to deal with HMRC on your behalf (checked 7 Oct 2026)
- TaxAid: About us (checked 8 Oct 2026)
- Citizens Advice: About us (checked 7 Oct 2026)