La Liga clubs sold players worth 480 million euros in the transfer window which closed on Monday.
Madrid: La Liga clubs earned more from player sales in the close season than any league in history, including a record amount from selling talent to rivals abroad, according to a study published on Thursday.
The figures compiled by Barcelona-based Prime Time Sport underlined how Spanish top-flight teams, excluding wealthy Real Madrid and Barcelona, are increasingly being forced to cash in on top performers to stay afloat.
They also suggested UEFA's Financial Fair Play (FFP) rules, currently being phased in and designed to prevent clubs spending more than they earn, are beginning to bite.
La Liga clubs sold players worth 480 million euros in the transfer window which closed on Monday, Prime Time's latest Football Transfer Review showed. Almost a third of income, or 139 million euros, came from deals with clubs outside Spain.
The majority of players were sold to English Premier League sides, including Mesut Ozil leaving Real Madrid for Arsenal, Alvaro Negredo and Jesus Navas joining Manchester City from Sevilla and Roberto Soldado switching to Tottenham Hotspur from Valencia.
La Liga clubs spent 388 million euros buying players, the second highest amount ever, yielding a net profit of 92 million, with Real (183 million) and Barca (57 million) accounting for 62 per cent of the outlay.
However, outside the big two, the world's richest clubs by income, four clubs did not spend anything at all on players and nine laid out less than 3 million euros each.
"La Liga is now more of a seller than a buyer and except for Real and Barca is experiencing difficulties in holding on to talent," Prime Time said.
"As many as 13 of the 20 teams in La Liga took their chance to cash in and clean up their accounts."
The study also showed that after Real's purchase of Gareth Bale from Spurs for a record 100 million euros the club has spent 611 million on players in the past five years, almost 40 percent of the total for La Liga.
They have spent 75 percent more than arch-rivals Barca (348 million), who bought only one player in the close season - Brazil forward Neymar from Santos for 57 million euros - for the first time in a quarter of a century.
Real were also the most active club in selling talent, reaping 260 million euros over the past five seasons ahead of Atletico Madrid on 220 million, Valencia 215 million and Barca 145 million.
"Financial constraints and availability of top players have put Atletico and Valencia very close to Real Madrid over a five-year period," Prime Time said.
"Barcelona are traditionally more reluctant to sell its best players," they added. Barca have the joint-most players from their own academy with 17, the same as Athletic Bilbao who only field players of Basque origin, Prime Time said.