Green’s Dictionary of Slang

(US) mind your own busin ess; also extended to p.m.y.o.b., please...

1915		P.W. Long ‘Semi-Secret Abbreviations’ in DN IV:iii 246: m.y.o.b., mind your own business.
1953		J. Franklyn Cockney 273: ‘Mind your own’, or ‘M.Y.O.B.’, is felt to be less quarrelsome and aggressive than the phrase in full.
1959		I. & P. Opie Lore and Lang. of Schoolchildren (1977) 203: ‘M.Y.O.B.’, Mind your own beeswax’, ‘Mind your own biz’.
2006		P. Carey Theft 267: Where did this money come from? myob.
2024		J. Meades Empty Wigs (t/s) 668: Just walk by. Don’t get involved. MYOB.