Manchester City and Paris Saint-Germain are likely to suffer when UEFA's Financial Fair Play ruling comes into play next year.
The defending English Premier League champions and Ligue 1 leaders are among the richest clubs in the world but failure to break even could see them excluded from future European competitions.
UEFA's policy stipulates that clubs can only report a maximum loss of €45 million over three seasons – a figure City have reportedly more than doubled.
Champions League winners Chelsea would also fall short of the requirements, while 46 teams across Europe failed to break even in the past three seasons.
UEFA have warned the three big-spending clubs there will be heavy scrutiny of their sponsorship deals.
Gianni Infantino, the UEFA general secretary, said clubs needed to show they were meeting the criteria, not investing money through sponsorship arrangements.
"Everyone including Paris Saint Germain or any other club, they know the rules, they know when they kick in and they know what they have to demonstrate," he said.
"A related party cannot just inject money into a club directly or indirectly though different systems."