Financial Fair Play (FFP) has created a bigger divide in football since its inception in 2012, according to economists at a university in Germany.
Uefa introduced FFP regulations with an aim to "improve the overall financial health of European club football".
Economists studied activity in England, France, Germany, Italy and Spain for a decade to determine FFP's impact.
Their study says barriers to investors prove a "disadvantage to smaller clubs" and create less competition.
"Uefa Financial Fair Play didn't reduce inequality between clubs, but rather increased it further," said Professor Christoph Kaserer, from the Technical University of Munich.
The study said FFP "solidifies existing hierarchies" as it does not allow financially weaker clubs to progress via means of investment.
"Investors can break up established structures and thus strengthen competition," added Dr Daniel Urban.
However, the study suggested steps taken by Uefa for the FFP period between 2015 and 2018 in order to help clubs experiencing financial upheaval were "a step in the right direction".
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