The following list shows all the companies that are in the game.
| Companies List | |||
| Pos. | Company Name | Awards | Total Worth |
| 16401 | one more wont hurt | £ 38,120,600 | |
| 16402 | one of craze | £ 398,067,001 | |
| 16403 | One Piece | £ 11,282,781 | |
| 16404 | One Piece. | £ 40,965,499 | |
| 16405 | One Pound Fish | £ 1,584,921 | |
| 16406 | One Pound Transfers | £ -2,799,952 | |
| 16407 | One Shot | £ 123,851,456 | |
| 16408 | One Silence | £ -4,074 | |
| 16409 | One to Many. | £ 4,976,234 | |
| 16410 | one too many pints | £ 353,128,608 | |
| 16411 | One United | £ 5,379,005 | |
| 16412 | OneHATE | £ 67,247,345 | |
| 16413 | Onenos | £ 115,119,975 | |
| 16414 | oneone | £ 18,206,569 | |
| 16415 | Oner | £ 10,516,756 | |
| 16416 | OneStopEnvelopeShoppe | £ -38,952 | |
| 16417 | Onetical | £ 5,502,381 | |
| 16418 | Onioninc | £ -43,613 | |
| 16419 | Onions | £ 56,031,337 | |
| 16420 | ONLINE GAMES | £ 163,665,298 | |
| 16421 | online games. | £ 167,252,652 | |
| 16422 | Only 50k | £ 120,794,156 | |
| 16423 | Only Bombs Allowed | £ 57,741,277 | |
| 16424 | Only Fools and Horses | £ 859,719,219 | |
| 16425 | Only Grans | £ 122,787,706 | |
| 16426 | only me | £ 50,000 | |
| 16427 | only me inc | £ 133,078,068 | |
| 16428 | OnlyDollars | £ 929,042 | |
| 16429 | OnlyMoney | £ 4,556,121 | |
| 16430 | OnlyProfits | £ 5,059,024 | |
| 16431 | OnlyStocks | £ 4,382,795 | |
| 16432 | Onomatopoeias | £ 939,660 | |
| 16433 | Onshore Money | £ 104,918,400 | |
| 16434 | Onslaught | £ 173,378,826 | |
| 16435 | Ontara | £ 79,736,570 | |
| 16436 | Ontario | £ 159,783,223 | |
| 16437 | ontheblock | £ 6,402,837 | |
| 16438 | Onyx | £ 429,592 | |
| 16439 | OO7 | £ 24,682,212 | |
| 16440 | Ooglaigh na Heireann | £ 240,713,877 | |
| 16441 | oohyeaa | £ 50,844,745 | |
| 16442 | Oolacile-01 | £ 3,643,194 | |
| 16443 | oOoOo | £ 82,717,145 | |
| 16444 | oooooo | £ 5,505,528 | |
| 16445 | OOOoooOOO | £ 18,588,312 | |
| 16446 | oooPPPooo | £ -53,065 | |
| 16447 | oops | £ 965,477 | |
| 16448 | ooz | £ 320,966,832 | |
| 16449 | Opal Opal | £ 5,502,194 | |
| 16450 | Opec | £ 1,574,677,165 | |
| 16451 | Opel Dire | £ 5,505,993 | |
| 16452 | Open AI | £ 50,000 | |
| 16453 | OpEn FoR BuIsNeSs | £ 5,785,269 | |
| 16454 | OpenAI | £ 45,638,249 | |
| 16455 | Openhammer | £ 37,087,124 | |
| 16456 | Opera House | £ 123,137,933 | |
| 16457 | operating systems | £ 42,894,228 | |
| 16458 | Operation Centerboard | £ 45,661,943 | |
| 16459 | OPERATION SEALION | £ 10,353,786 | |
| 16460 | OPERATION SEALION 2 | £ 5,504,218 | |
| 16461 | Ophthalmology | £ 45,575,639 | |
| 16462 | Opinion | £ 389,953,431 | |
| 16463 | OPiuM | £ 115,856,941 | |
| 16464 | Oppa Gangnam Style | £ 65,242,420 | |
| 16465 | Oppenheim | £ 51,959,450 | |
| 16466 | Oppertunity | £ 512,316,834 | |
| 16467 | Opportunities | £ 58,183,350 | |
| 16468 | Opportunity | £ 11,354,079 | |
| 16469 | Opposition | £ 761,831,311 | |
| 16470 | Oppression | £ 416,055,267 | |
| 16471 | optics | £ 57,286,889 | |
| 16472 | Optimal Flames | £ 175,592,178 | |
| 16473 | Optimum Nutrition | £ -3,018,246 | |
| 16474 | Optimus Inc. | £ -2,482,292 | |
| 16475 | Options | £ 84,494,650 | |
| 16476 | Options Trading | £ 15,395,474 | |
| 16477 | Opus Dei | £ 1,714,492,650 | |
| 16478 | opus technology | £ 35,372,824 | |
| 16479 | Or Fords | £ 43,656,592 | |
| 16480 | Oracle | £ 5,067,108 | |
| 16481 | Orakos | £ 9,653,572 | |
| 16482 | Orange | £ 24,725,264 | |
| 16483 | Orange Aftershock | £ 67,681,186 | |
| 16484 | Orange Castle | £ 615,362 | |
| 16485 | Orange County | £ 4,910,507 | |
| 16486 | Orange Creatine | £ 6,196,167 | |
| 16487 | Orange Jelly | £ 6,594,926 | |
| 16488 | Orange Jooze | £ 1,261,621 | |
| 16489 | Orange Jooze 3 | £ 50,000 | |
| 16490 | Orange Jooze2 | £ 795,888 | |
| 16491 | Orange Jooze4 | £ 50,000 | |
| 16492 | Orange Jooze5 | £ 50,000 | |
| 16493 | Orange Paint | £ 97,288,036 | |
| 16494 | Oranginal | £ 4,103,756 | |
| 16495 | oranje | £ 4,966,784 | |
| 16496 | Orbital | £ 54,539,946 | |
| 16497 | Orbital Bombardment | £ 1,279,471,445 | |
| 16498 | Orbital Mechanics | £ 190,596,789 | |
| 16499 | Orbital Oasis | £ 61,220,273 | |
| 16500 | Orchids R Us Ltd | £ 39,331,588 | |
