Merger talks between Spanish lenders BBVA and Banco Sabadell ended on Friday (November 27).
The two banks had recently announced merger talks on November 16 - their aim was to build Spain's second-biggest bank with almost 600 billion euros in assets.
Just days after that, though, BBVA Chief Executive Onur Genc said he was in no rush.
He said the bank would analyse everything and that it also had other options.
Both banks announced the end of talks in separate statements.
No details of the financial disagreement were disclosed by the banks.
Spanish newspaper El Economista had reported Thursday that BBVA was willing to pay in cash as demanded by Sabadell.
But it did not consider substantially increasing its potential offer of around 2.5 billion euros - or close to $3 billion.
The collapse piles pressure on Sabadell, which was seen as the weaker partner.
The smaller Spanish bank said it would announce a new business plan, with a focus on its home market, in the first quarter of 2021.
It is also a blow to banking consolidation in Spain and leaves the future of Sabadell's British lender TSB unclear.
Shares in Sabadell fell 13% early Friday.
Before that stocks at both banks had risen close to 20% since the announcement of merger talks.