CaixaBank, the third-biggest Spanish bank by capitalisation, reported on Thursday an 84-percent drop in its 2012 first-quarter net profit owing to large capital provisions for risky loans.
The fall was on a 12-month comparison. Caixa said its net profit amounted to just 48 million euros ($63 million).
Investors quickly sold off shares in the bank, which fell by 0.58 percent to 2.589 euros in early trading on the Madrid stock exchange, which was 0.82 percent higher overall.
Caixa also said in a statement to the Spanish financial markets regulator CNMV that the bank's first-quarter net banking income rose by 10.2 percent to 883 million euros, and that its operating margin rose to 25.3 percent.
Net banking income is an important measure of the difference between what a bank pays to attract funds and what it charges for lending them.
Those results and cash reserves "allowed it to fully absorb the provisions in the first quarter," the statement said.
In February, Caixa said it would take 2.436 billion euros in provisions to cover potential losses in problematic real-estate activities.
On Wednesday, the Spanish central bank said that the ratio of bad loans at the nation's banks shot to an 18-year high level of 8.15 percent in February as the banks struggled with a mass of deteriorating property-related loans.
CaixaBank said that its rate of risky loans rose to 5.25 percent at the end of March from 4.9 percent at the end of December and 3.65 percent at the end of 2010.
In late March, the bank announced that it would buy the savings bank Banca Civica for 977 million euros, which would make Caixa the biggest Spanish bank by assets, but did not integrate Civica's results in the first-quarter data.
Caixa said that after the acquisition was finalised later this year, it would be "the biggest entity in Spain, with total assets of 342 billion euros, more than 14 million clients, a 14 percent share of deposits and 13.4 percent of credits."
Caixa's core Tier 1 capital, a benchmark of its ability to resist financial shocks reached a healthy 12.4 percent at the end of March, compared with 8.9 percent in 2010.
Spanish banks are a key concern to financial markets because of the falling value of huge loans they allowed to build up during a property bubble that collapsed in 2008.
The government has ordered banks to increase provisions as that concern has made it harder for banks and the government to borrow funds on interbank and bond markets.