The O2 Arena in London has made a combined net profit of $203.7m (€166m/£146.m) since 2002 when sports conglomerate AEG acquired the venue.
The facility opened as a theme park to celebrate the new Millennium, but failed to live up to expectations, attracting just over half of its expected visitors during its 12-month lifespan.
Having cost approximately $976m to construct and $1.4m a month to maintain, the British government opted to sell the venue to AEG in order to save on costs and retrieve some of the funds.
AEG turned the facility into a 21,000-seater entertainment venue that now hosts a plethora of events, ranging from music concerts to sports championships.
In a further boost, AEG brought O2, a subsidiary of Spanish telecommunications giant Telefónica on board as naming rights partner. This deal was renewed last year until a least 2027, for a cost of around $174m.
Citing a report in the Daily Telegraph newspaper, Forbes said such has been the success of the project that the venue has made a profit after tax each year since 2008.
In 2017, profit after tax hit a record high, surging 13.3% year-on-year to $46.7m, while total audience came in at a record 2.7 million, driving revenue to $134.8m.