Barcelona's summer asset sale allowed them to lift their salary cap from minus 144.3 million euros ($144.8 million)in March to a positive balance of 656.4 million by September, La Liga reported Friday.
The Spanish league made public the salary limits available to teams after the summer transfer window.
The figures reveal the complete transformation of Barcelona's finances and the huge divide between the richest clubs and the rest.
Barcelona spent some 153 million euros on transfer fees alone as they splurged on a platoon of stars including Robert Lewandowski, Raphinha and Jules Kounde and free agents Andreas Christensen and Franck Kessie, but took in far more by selling future rights.
The club sold 25 percent of their domestic television rights for the next quarter of a century to US investment firm Sixth Street for around 400 million euros and just under 50 percent of Barca Studios, which manages the club's digital business and audiovisual productions, to two investors for 200 million euros.
La Liga updates the salary cap, based on the difference between revenue and costs, several times each season.
The cap specifies the amount clubs can spend on players, head coach, assistant coach and the first-team fitness coach as well as subsidiaries and youth academies.
Real Madrid continue to lead with a cap of 683.4 million euros, down from 739 million euros last March.
Barcelona are now just behind. There is a significant gap to Atletico Madrid, who are third, on 341 million euros with Sevilla next on almost 200 million euros. Eight clubs have caps of 52 million euros or less.
Real Madrid's salary cap is bigger than the total for the 12 clubs with the smallest caps added together.