La Liga are pushing for Manchester City to be investigated by UEFA concerning breaches of their Financial Fair Play rules.
The European governing body have already announced they are looking into Paris Saint-Germain following their mega deals for Neymar and Kylian Mbappe.
La Liga president Javier Tebas has spoken of concerns regarding "funding by state-aid" with his belief that it "distorts European competitions and creates an inflationary spiral that is irreparably harming the football industry."
Pep Guardiola's side have spent lavishly this summer, forking out £220m to overhaul their squad to his liking, the largest spending spree of all time in a single window.
A statement from the body released on Monday confirmed two letters were sent to UEFA on August 22, urging them to investigate both PSG and City.
It read: "Both PSG and Man City benefit from sponsorships that make no economic sense and lack any fair value.
"La Liga calls on Uefa to proceed with its investigation, taking into account the full history of PSG's actions. Additionally, La Liga calls on Uefa to open a similar investigation into Man City."
PSG are owned by the state of Qatar, while City benefit from The Abu Dhabi United Group's investment.
La Liga are thought to be angered after PSG triggered Neymar's release clause, refusing the initial payment.
After opening proceedings concerning PSG meeting the regulations, a UEFA statement read: "The investigation will focus on the compliance of the club with the break-even requirement, particularly in light of its recent transfer activity."
The news leaves La Liga open to accusations of hypocrisy after Spanish football clubs were forced to repay tens of millions in illegal state subsidies last year.
Real Madrid, Barcelona, Valencia, Athletico Bilbao, Osasuna, Hercules and Elche were all forced to repay sums ranging from €3.7m to €18.4m.