| Nicklin LLP | | | accounting fraud or deficiencies | 2021 | UK-ICAEW | £525 |
| Nickalls Accountants Limited | | | accounting fraud or deficiencies | 2022 | UK-ICAEW | £840 |
| Nicholas Kumasi Ltd | | | tax violations | 2017 | UK-HMRC | £977,819 |
| Nicholas Greaves Associates Limited EAB | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £14,000 |
| Nguyen Properties UK Ltd EAB | | | anti-money-laundering deficiencies | 2023 | UK-HMRC | £1,950 |
| NGS Samra Limited fka Star Fish Bar | | | tax violations | 2024 | UK-HMRC | £57,111 |
| NFS Software Ltd | | | tax violations | 2021 | UK-HMRC | £390,865 |
| Next4UK Consulting Ltd | | | anti-money-laundering deficiencies | 2019 | UK-HMRC | £500 |
| Next Move Estates (Manchester) Ltd EAB | | | anti-money-laundering deficiencies | 2023 | UK-HMRC | £1,550 |
| Next Level Business Limited | | | accounting fraud or deficiencies | 2021 | UK-ICAEW | £2,944 |
| Nexis Solutions Limited ASP | | | anti-money-laundering deficiencies | 2023 | UK-HMRC | £1,250 |
| Nexia Smith & Williamson Audit Limited | | | accounting fraud or deficiencies | 2020 | UK-ICAEW | £254,248 |
| News 'n' Chews | | | tax violations | 2018 | UK-HMRC | £34,004 |
| Newmore Ltd EAB | | | anti-money-laundering deficiencies | 2023 | UK-HMRC | £2,750 |
| Newlinks London Ltd | | | anti-money-laundering deficiencies | 2020 | UK-HMRC | £0 |
| Newland Park Manor Ltd | | | tax violations | 2017 | UK-HMRC | £195,081 |
| Newhome Scotland Limited EAB | | | anti-money-laundering deficiencies | 2023 | UK-HMRC | £2,750 |
| Newhold Limited | | | tax violations | 2019 | UK-HMRC | £86,988 |
| Newham Pizza Ltd dba TGF Pizza | | | tax violations | 2018 | UK-HMRC | £192,668 |
| Newglobe Resources Limited | | | tax violations | 2022 | UK-HMRC | £367,247 |
| Newford Payless Limited | | | tax violations | 2017 | UK-HMRC | £63,235 |
| Newday Trading Limited | | | tax violations | 2023 | UK-HMRC | £170,848 |
| Newbridge Fish Bar Limited | | | tax violations | 2016 | UK-HMRC | £20,740 |
| New Sung Chop Suey Ltd | | | tax violations | 2016 | UK-HMRC | £40,539 |
| New Silvertex Limited | | | tax violations | 2016 | UK-HMRC | £28,237 |
| New Ship Pub Ltd dba The New Ship | | | tax violations | 2022 | UK-HMRC | £16,839 |
| New Phoenix | | | tax violations | 2022 | UK-HMRC | £27,844 |
| New Palace Ltd dba Tim's Palace | | | tax violations | 2019 | UK-HMRC | £74,945 |
| New Lucky House Dundee Limited dba The Lucky House | | | tax violations | 2017 | UK-HMRC | £76,291 |
| New House Farm (Lorton) Ltd | | | tax violations | 2023 | UK-HMRC | £11,972 |
| New Golden Chef | | | tax violations | 2018 | UK-HMRC | £44,109 |
| New Generation Training and Consultancy Limited | | | tax violations | 2019 | UK-HMRC | £83,352 |
| New Gables Restaurant Limited | | | tax violations | 2020 | UK-HMRC | £75,889 |
| New Fujiyama Limited | | | tax violations | 2023 | UK-HMRC | £48,344 |
| New Emperor Trading Limited | | | tax violations | 2020 | UK-HMRC | £22,464 |
| New Darjeeling Ltd dba Darjeeling Restaurant | | | tax violations | 2018 | UK-HMRC | £58,185 |
| New Collection Leicester Ltd | | | tax violations | 2020 | UK-HMRC | £28,378 |
| New Bramber Dragon Restaurant | | | tax violations | 2018 | UK-HMRC | £21,078 |
| New Bharat Coaches Limited | | | tax violations | 2022 | UK-HMRC | £65,275 |
| New Ariana Exchange Ltd | | | anti-money-laundering deficiencies | 2020 | UK-HMRC | £0 |
| Netofa Limited ASP | | | anti-money-laundering deficiencies | 2021 | UK-HMRC | £1,250 |
| Netimex Verhuur BV | | | tax violations | 2021 | UK-HMRC | £12,922 |
| Net Accounts Limited ASP | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £6,470 |
| Nestor Healthcare Group Limited | | | investor protection violation | 2013 | UK-FSA | £175,000 |
| Neil Turner Associates Limited | | | tax violations | 2023 | UK-HMRC | £34,645 |
| Nedbank Private Wealth Limited | | | anti-money-laundering deficiencies | 2023 | UK-IOM | £535,185 |
| Neagra UK Construction Ltd | | | tax violations | 2024 | UK-HMRC | £37,238 |
| NB Supersave Limited franchise of Day-Today | | | tax violations | 2018 | UK-HMRC | £33,407 |
| NB Estate Agents Limited EAB | | | anti-money-laundering deficiencies | 2023 | UK-HMRC | £13,600 |
| Nazar Ltd formerly trading as Kebab King | | | tax violations | 2023 | UK-HMRC | £147,670 |
| Naz Bedford Limited dba Nazar Restaurant | | | tax violations | 2020 | UK-HMRC | £110,945 |
| Nawaz Food Store | | | tax violations | 2019 | UK-HMRC | £17,146 |
| Nationwide Building Society | Nationwide Building Society | financial services | banking violation | 2020 | UK-CMA | £900,000 |
| Nationwide Building Society | Nationwide Building Society | financial services | banking violation | 2019 | UK-CMA | £6,000,000 |
| National Westminster Bank plc | NatWest Group PLC | financial services | anti-money-laundering deficiencies | 2021 | UK-FCA | £264,772,619 |
| Nathan Samuel Limited | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £0 |
| Natalie Malka Property Ltd EAB | | | anti-money-laundering deficiencies | 2023 | UK-HMRC | £4,100 |
| Natalie Clarke Residential Limited EAB | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £14,500 |
| Naren & Associates Limited ASP | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £4,386 |
| Nan Indian Cuisine Ltd | | | tax violations | 2018 | UK-HMRC | £20,961 |
| Nako | | | tax violations | 2019 | UK-HMRC | £46,315 |
| Najma Group Ltd dba Cafe Muse | | | tax violations | 2022 | UK-HMRC | £39,961 |
| Nails@555 Limited fka Nails @5 Limited | | | tax violations | 2023 | UK-HMRC | £116,981 |
| Nails & Beauty Limited | | | tax violations | 2020 | UK-HMRC | £48,480 |
| Nail Express | | | tax violations | 2019 | UK-HMRC | £13,615 |
| Nahid Residential Limited | | | tax violations | 2020 | UK-HMRC | £118,956 |
| Nafeez Takeaway | | | tax violations | 2016 | UK-HMRC | £42,613 |
| Nachi Ltd | | | tax violations | 2019 | UK-HMRC | £329,505 |
| N9 Beijing Limited formerly trading as Chef Beijing | | | tax violations | 2023 | UK-HMRC | £71,422 |
| N.S. Amin & Co | | | accounting fraud or deficiencies | 2019 | UK-ICAEW | £1,000 |
| N-Hanced LLP | | | investor protection violation | 2010 | UK-FSA | £21,000 |
| N&M Paradise Ltd | | | tax violations | 2024 | UK-HMRC | £107,137 |
| N T Accountancy Services Limited ASP | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £4,455 |
| Myrings Estate Agents Ltd EAB | | | anti-money-laundering deficiencies | 2023 | UK-HMRC | £15,600 |
| Myint Construction Ltd | | | tax violations | 2021 | UK-HMRC | £28,772 |
| Myers Clark Limited | | | accounting fraud or deficiencies | 2017 | UK-ICAEW | £5,980 |
| MY.KLT Ltd | | | tax violations | 2018 | UK-HMRC | £2,713,705 |
| My Sales Limited EAB | | | anti-money-laundering deficiencies | 2022 | UK-HMRC | £3,561 |
| My Favourite Chicken Ltd dba Sopranos | | | tax violations | 2021 | UK-HMRC | £49,185 |
| MVF South Shields Limited dba Man V Food | | | tax violations | 2018 | UK-HMRC | £15,308 |
| Mustafa&Co Property Management Ltd EAB | | | anti-money-laundering deficiencies | 2023 | UK-HMRC | £4,500 |
| Murry Harcourt Limited | | | accounting fraud or deficiencies | 2019 | UK-ICAEW | £1,072 |
| Murdock & Wasley Estate Agents Ltd EAB | | | anti-money-laundering deficiencies | 2023 | UK-HMRC | £13,600 |
| Muras Baker Jones Limited | | | accounting fraud or deficiencies | 2023 | UK-ICAEW | £3,656 |
| Muranda Electrical Services Ltd | | | tax violations | 2020 | UK-HMRC | £499,203 |
| Mumtaz Food Products Ltd | | | tax violations | 2023 | UK-HMRC | £40,938 |
| Mumbai Junction Ltd | | | tax violations | 2019 | UK-HMRC | £626,462 |
| Multi MD Limited | | | tax violations | 2021 | UK-HMRC | £76,910 |
| MUFG Securities EMEA plc | Mitsubishi UFJ Financial Group | financial services | internal controls deficiency | 2017 | UK-PRA | £8,925,000 |
| Mude Ltd dba Big Chef Cafe & Restaurant | | | tax violations | 2018 | UK-HMRC | £76,775 |
| MTQ Estates Private Limited EAB | | | anti-money-laundering deficiencies | 2023 | UK-HMRC | £2,750 |
| MT Global Ltd | | | anti-money-laundering deficiencies | 2021 | UK-HMRC | £1,994,007 |
| MT Global Ltd | | | anti-money-laundering deficiencies | 2020 | UK-HMRC | £0 |
| MSW Consultants Limited | | | tax violations | 2023 | UK-HMRC | £24,047 |
| MSR Partners LLP | | | accounting fraud or deficiencies | 2019 | UK-ICAEW | £455,813 |
| MSR Partners LLP | | | accounting fraud or deficiencies | 2019 | UK-ICAEW | £30,693 |
| Mslon Ltd | | | tax violations | 2023 | UK-HMRC | £132,621 |
| MSK 9 Limited EAB | | | anti-money-laundering deficiencies | 2023 | UK-HMRC | £2,750 |
| MSA Group (UK) Ltd | | | tax violations | 2021 | UK-HMRC | £67,981 |
| Mr Q Chinese Takeaway | | | tax violations | 2023 | UK-HMRC | £81,735 |
| Mr Food Design Limited | | | tax violations | 2019 | UK-HMRC | £232,482 |
