Barcelona trying to keep Lionel Messi could have put the club at risk for 50 years, says president Joan Laporta.
Messi, 34, is leaving because they could not afford to give him a new contract under La Liga's salary limit.
A private equity firm wanted to invest in La Liga, which could have made signing Messi possible, but would have meant Barca giving up some TV rights.
"I can't make a decision that will affect the club for 50 years," Laporta said.
"The club is over 100 years old and it's above everyone and everything, even above the best player of the world. We will always thank him for everything he's done for us.
"In order to have fair play, we need to do this or make an effort which would put the club at risk. We couldn't keep going with this and we needed to make a decision, which we have."
Messi, Barcelona's all-time leading goalscorer, had agreed a new five-year contract on reduced wages – but the club still had to slash their wage bill to afford him, and were unable to do so.
"Leo wanted to stay, so he's not happy," Laporta said. "We all wanted him to stay. For him, he has to confront reality. It's a reality that can't be changed and he knows I wish him the best wherever he goes."
Laporta added that he did not want to give "false hope" on "hypothetical" ideas that would see keeping Messi possible. "This negotiation has ended," he said.
Paris St-Germain have begun to explore the feasibility of signing Messi.
'There will be a before and after Leo'
Messi is Barcelona's record scorer with 672 goals and has won 10 La Liga titles, four Champions Leagues and the Copa del Rey seven times, as well as claiming the Ballon d'Or on a record six occasions.
"Leo's legacy is excellent. He's made history," Laporta said. "He's the player with the most success in history of the club.
"He's been the reference of an era which has been splendid. The best era of Barca's history until today.
"A new era starts now. There will be a before and after Leo. We need to be eternally thankful to him."
Laporta revealed that the aim had been for Messi to stay for two more years – even though he had agreed a five-year deal.
"Obviously it's sad the situation is what it is – that with Covid, we can't pay homage to him in a way we would have wanted to do in two years with fans in the stands.
"We were all thinking two years and then if he wanted more we could negotiate. We wanted the post-Messi era to start in two years. Taking into account the circumstances, we've had to bring it forward."
'We thought La Liga would be more flexible'
Private equity firm CVC wanted to invest 2.7bn euros into La Liga in exchange for 10% revenue and a 10% stake in most of its business, but Barca – who felt it would affect future TV deals – and Real Madrid opposed the deal.
"The only way to have that salary margin now was to accept the operation we don't think is interesting for Barcelona," Laporta said.
"It's an operation that puts at risk the club for the next 50 years. We can't do that."
Laporta, who became president in March after Josep Maria Bartomeu stepped down in October – says a recent audit shows the club's financial situation is worse than they expected – and that he initially thought La Liga would allow their new contract with Messi.
"We haven't had six months [to sort this out]," he said. "We've had less because the audit numbers have just come out.
"The initial figures, we've realised the situation is even worse than expected. We've gone from bad to worse."
Laporta admitted he thought La Liga would "be more flexible with fair play" and accept their contract proposals with Messi.
"The first offer was two years of salary to be paid in five," Laporta said. "When we thought that would be allowed in FFP, the criteria of cash came into play.
"It's not allowed here, while it is in other countries. La Liga had its pressures because other clubs want the regulations and rules to be abided by.
"Then we agreed a five-year contract. We thought that would be allowed by FFP regulations, and I had insinuated in a convincing way this would be allowed, but after a technical analysis by the La Liga commission, we found out it wouldn't be valid within those regulations."
Messi's exit has taken Barcelona's wage bill is down from 110% of their income to 95%.
"We're at the limit even without Leo," he said. "We need to recalculate but we're over the salary limit."
Laporta hopes the club will be able to register new signings such as Sergio Aguero, Memphis Depay, Emerson and Eric Garcia now Messi has gone.
"These are players coming to Barca accepting certain salary conditions and we have to thank them for that," he said.
"The arrival of these players isn't comparable to what it would have meant to formalise the agreements with Messi in terms of FFP."
'Messi is in shock… PSG the only option' – how a dramatic day unfurled
Spanish football writer Guillem Balague
For the first hour, I was in denial because it's a story of twists and turns, the club and player have worked really hard to make it happen. I thought Barcelona were putting pressure on La Liga.
There is the limit in wages that La Liga forces on teams. Barca have a huge debt.
I thought 'no – this can't be everything finishing here'. But it is finishing here. I am saying that having read through the public note and phone calls, I found out that it has been a strange day.
Messi and his father and agent Jorge Messi came to Barcelona for the confirmation that a new contract was going to be signed. Everything had been agreed for three weeks.
But president Joan Laporta told Jorge Messi they had looked into the detail, not only of the contract but of the new financial deal La Liga have reached [with private equity firm CVC] and 15% of that money can go to wages.
They saw this was not enough to beat financial fair play. It cannot be done.
A lot of the players Barcelona wanted to get rid of don't want to go. Antoine Griezmann, Jordi Alba, Gerard Pique, all that is not happening. It means even though Messi had reduced his wages by 50%, Barcelona cannot afford him.
The plan was for him to earn 20m euros next season, and not be the best-paid player for Barcelona. If that is the case, why did Laporta want to meet on Thursday to sign a new contract?
Messi is in shock – PSG seems to be the only option. A league not so competitive, where he can rest and prepare for the World Cup and then go to the United States. It has to be PSG.
It will take a while to get over this. It is Barcelona saying: 'We are going a different direction, not putting pressure on La Liga.' It's very difficult to take.