| Netofa Limited ASP | | | anti-money-laundering deficiencies | 2021 | UK-HMRC | £1,250 |
| New Ariana Exchange Ltd | | | anti-money-laundering deficiencies | 2020 | UK-HMRC | £0 |
| New Bharat Coaches Limited | | | tax violations | 2022 | UK-HMRC | £65,275 |
| New Bramber Dragon Restaurant | | | tax violations | 2018 | UK-HMRC | £21,078 |
| New Collection Leicester Ltd | | | tax violations | 2020 | UK-HMRC | £28,378 |
| New Darjeeling Ltd dba Darjeeling Restaurant | | | tax violations | 2018 | UK-HMRC | £58,185 |
| New Emperor Trading Limited | | | tax violations | 2020 | UK-HMRC | £22,464 |
| New Gables Restaurant Limited | | | tax violations | 2020 | UK-HMRC | £75,889 |
| New Generation Training and Consultancy Limited | | | tax violations | 2019 | UK-HMRC | £83,352 |
| New Golden Chef | | | tax violations | 2018 | UK-HMRC | £44,109 |
| New House Farm (Lorton) Ltd | | | tax violations | 2023 | UK-HMRC | £11,972 |
| New Lucky House Dundee Limited dba The Lucky House | | | tax violations | 2017 | UK-HMRC | £76,291 |
| New Palace Ltd dba Tim's Palace | | | tax violations | 2019 | UK-HMRC | £74,945 |
| New Phoenix | | | tax violations | 2022 | UK-HMRC | £27,844 |
| New Ship Pub Ltd dba The New Ship | | | tax violations | 2022 | UK-HMRC | £16,839 |
| New Silvertex Limited | | | tax violations | 2016 | UK-HMRC | £28,237 |
| New Sung Chop Suey Ltd | | | tax violations | 2016 | UK-HMRC | £40,539 |
| Newbridge Fish Bar Limited | | | tax violations | 2016 | UK-HMRC | £20,740 |
| Newford Payless Limited | | | tax violations | 2017 | UK-HMRC | £63,235 |
| Newglobe Resources Limited | | | tax violations | 2022 | UK-HMRC | £367,247 |
| Newham Pizza Ltd dba TGF Pizza | | | tax violations | 2018 | UK-HMRC | £192,668 |
| Newhold Limited | | | tax violations | 2019 | UK-HMRC | £86,988 |
| Newland Park Manor Ltd | | | tax violations | 2017 | UK-HMRC | £195,081 |
| Newlinks London Ltd | | | anti-money-laundering deficiencies | 2020 | UK-HMRC | £0 |
| News 'n' Chews | | | tax violations | 2018 | UK-HMRC | £34,004 |
| Nexia Smith & Williamson Audit Limited | | | accounting fraud or deficiencies | 2020 | UK-ICAEW | £254,248 |
| Next Level Business Limited | | | accounting fraud or deficiencies | 2021 | UK-ICAEW | £2,944 |
| Next4UK Consulting Ltd | | | anti-money-laundering deficiencies | 2019 | UK-HMRC | £500 |
| NFS Software Ltd | | | tax violations | 2021 | UK-HMRC | £390,865 |
| Nicholas Greaves Associates Limited EAB | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £14,000 |
| Nicholas Kumasi Ltd | | | tax violations | 2017 | UK-HMRC | £977,819 |
| Nickalls Accountants Limited | | | accounting fraud or deficiencies | 2022 | UK-ICAEW | £840 |
| Nicklin LLP | | | accounting fraud or deficiencies | 2021 | UK-ICAEW | £525 |
| Nico Building Services | | | tax violations | 2022 | UK-HMRC | £18,141 |
| Nigel’s Barber Shop | | | tax violations | 2023 | UK-HMRC | £22,306 |
| Nino's Pizza | | | tax violations | 2018 | UK-HMRC | £27,168 |
| Niu Yashan Ltd | | | tax violations | 2018 | UK-HMRC | £358,241 |
| No. 4 Mayfair Limited | | | tax violations | 2019 | UK-HMRC | £281,698 |
| Noahs London Limited EAB | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £5,700 |
| Nolan Redshaw Limited EAB | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £14,039 |
| Nooris Brighton Ltd fka Nooris Indian Cuisine | | | tax violations | 2022 | UK-HMRC | £83,844 |
| Norcrown Limited dba Chasers Nightclub | | | tax violations | 2018 | UK-HMRC | £18,889 |
| Norfolk Property Online EAB | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £4,450 |
| North Star FWTD Ltd | | | tax violations | 2021 | UK-HMRC | £33,168 |
| North Swindon Limited | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £0 |
| North West Building and Design Limited | | | tax violations | 2016 | UK-HMRC | £59,771 |
| Northeast Shore Ltd Kinara Indian Restaurant | | | tax violations | 2019 | UK-HMRC | £26,564 |
| Northern Polymers Ltd | | | tax violations | 2019 | UK-HMRC | £773,075 |
| Northlight Surveying Ltd | | | tax violations | 2018 | UK-HMRC | £22,120 |
| Northstar Isolation Products Ltd | | | tax violations | 2019 | UK-HMRC | £20,648 |
| Norwich and Peterborough Building Society | Yorkshire Building Society | financial services | investor protection violation | 2011 | UK-FSA | £1,400,000 |
| Nova Inc Ltd dba The Harbour | | | tax violations | 2023 | UK-HMRC | £29,388 |
| Nova Scotia Homes Ltd dba Clyde & Forth Landholdings Ltd | | | tax violations | 2018 | UK-HMRC | £33,931 |
| NPP Plastering Ltd | | | tax violations | 2021 | UK-HMRC | £388,691 |
| NRR Entertainment Limited | | | tax violations | 2018 | UK-HMRC | £51,538 |
| NSAH (Alliance Homes) Limited EAB | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £4,000 |
| Number One Supermarket Ltd | | | tax violations | 2019 | UK-HMRC | £37,271 |
| Numbers (UK) Ltd | | | accounting fraud or deficiencies | 2019 | UK-ICAEW | £1,138 |
| Numble Limited ASP | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £6,888 |
| Numera Partners LLP | | | accounting fraud or deficiencies | 2023 | UK-ICAEW | £480 |
| Nurtenbirsen Limited dba Istanbul Kebab House | | | tax violations | 2021 | UK-HMRC | £40,745 |
| Nyman Libson Paul | | | accounting fraud or deficiencies | 2018 | UK-ICAEW | £4,393 |
| O'Hare News | | | tax violations | 2017 | UK-HMRC | £34,771 |
| O'Reilly Contract Scaffolding Ltd | | | tax violations | 2022 | UK-HMRC | £107,682 |
| O.B. Gallery Limited | | | tax violations | 2019 | UK-HMRC | £125,393 |
| O.C.O. Glenrothes Limited dba Pizza Hut Franchise | | | tax violations | 2019 | UK-HMRC | £19,351 |
| O.S.L | | | tax violations | 2017 | UK-HMRC | £127,957 |
| Oakleigh House Farm Ltd | | | tax violations | 2023 | UK-HMRC | £49,326 |
| Oakwood Letting & Estates Limited EAB | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £7,350 |
| Oatfield Developments Ltd | | | tax violations | 2020 | UK-HMRC | £309,846 |
| O’Connor Bowden Property Management (Manchester) Limited EAB | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £2,750 |
| O’Kane Bros Limited EAB | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £7,000 |
| OBC Group Ltd. fka Orchard Brickwork and Construction Ltd. | | | tax violations | 2022 | UK-HMRC | £69,168 |
| OBC The Accountants Limited | | | accounting fraud or deficiencies | 2018 | UK-ICAEW | £850 |
| Ocean Trawl Grimsby Limited | | | tax violations | 2021 | UK-HMRC | £92,957 |
| Ocwen Limited EAB | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £6,300 |
| Odyssey Construction Services Limited | | | tax violations | 2023 | UK-HMRC | £145,888 |
| Office Serv Limited TCSP | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £5,100 |
| Okrich Private Ltd franchise of Rollover | | | tax violations | 2017 | UK-HMRC | £78,007 |
| Old Hong Kong Ltd | | | tax violations | 2018 | UK-HMRC | £55,190 |
| Oliver & Akers Limited EAB | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £14,182 |
| Ollie’s Kebab & Pizza Limited fka Farnborough Pizza & Kebab Centre Limited. | | | tax violations | 2023 | UK-HMRC | £24,389 |
| Olympus Eyewear Europe Ltd | | | tax violations | 2019 | UK-HMRC | £85,766 |
| OME (HR Management) Corporation Ltd dba CTS Personnel Ltd. | | | tax violations | 2017 | UK-HMRC | £45,575 |
| Omega Plus Ltd dba Dynasty Chinese | | | tax violations | 2018 | UK-HMRC | £307,725 |
| On Site Recruitment Solutions Ltd | | | tax violations | 2021 | UK-HMRC | £174,637 |
| On Yip Restaurant Limited dba Hup Lee Buffet | | | tax violations | 2019 | UK-HMRC | £77,304 |
| Onestopmoneymanager Ltd | | | tax violations | 2022 | UK-HMRC | £64,139 |
| Ooki Takeaway Limited | | | tax violations | 2016 | UK-HMRC | £14,212 |
| Opco Leisure Ltd dba Casa | | | tax violations | 2022 | UK-HMRC | £70,417 |
| OPP Group Ltd | | | tax violations | 2021 | UK-HMRC | £325,707 |
| OPR Sports Management Ltd fka OPR Sports Consultancy Ltd | | | tax violations | 2018 | UK-HMRC | £32,300 |
| Orbis Wines and Spirits Limited dba Ds Warehouse | | | tax violations | 2016 | UK-HMRC | £17,078 |
| Orbit Hosting Ltd | | | tax violations | 2019 | UK-HMRC | £64,032 |
| Orchard Accountancy Services Limited ASP | | | anti-money-laundering deficiencies | 2021 | UK-HMRC | £10,030 |
| Oriental Express | | | tax violations | 2018 | UK-HMRC | £98,560 |
| Oriental Kitchen (Purley) Limited | | | tax violations | 2020 | UK-HMRC | £53,504 |
| Original 7 Spices Ltd | | | tax violations | 2023 | UK-HMRC | £19,489 |
| Originals SP Zo.o | | | tax violations | 2023 | UK-HMRC | £1,856,628 |
| Orinsen Limited EAB | | | anti-money-laundering deficiencies | 2021 | UK-HMRC | £13,100 |
| Ormeau 2016 Limited dba CBSWM12 Limited dba CBS Astor Buller Limited | | | tax violations | 2016 | UK-HMRC | £19,958 |
