Citigroup was one of four large US banks that flunked stress tests aimed at seeing how they would hold up in a new economic crisis, Federal Reserve data showed Tuesday.

Three others — Ally, Suntrust and MetLife — also failed the tests, while 15 other large bank holding companies passed the exercise, the Fed said.

As a group, though, the 19 came through strongly, said the Fed, thanks to pressure for them to boost capital over the past three years as the financial sector digs its way out of the deep 2008-2009 recession.

“In fact, despite the significant projected capital declines, 15 of the 19 bank holding companies were estimated to maintain capital ratios above all four of the regulatory minimum levels under the hypothetical stress scenario,” the Fed said.

The exercise opened the door for some of the most capital-flush banks to immediately announce new or higher dividend payments to shareholders, after the Fed prevented or limited such payouts by a number of the banks last year following a similar examination.

JPMorgan Chase announced a 20 percent dividend hike and a $15 billion share buyback program, while Wells Fargo also sharply boosted its planned dividend.

Bank shares meanwhile surged in the final hour of trade on the US markets after JPMorgan jumped the gun with its announcement that it had passed the tests and would up its dividend.

The Fed had originally planned to release the results on Thursday.

The central bank’s test subjected the banks to another theoretical crash of the economy to see how they would hold up: a US recession marked by a 50 percent drop in stock prices, a 21 percent fall in housing prices, and joblessness soaring to 13 percent, all the while being buffeted by an even worse recession in Europe.

The test saw the 19 together losing $534 billion over nine months.

Despite that, the Fed said, at the end of the test period the banks together had core “tier one” capital at a level that was higher than the actual level they had during the financial crisis in early 2009.

That “reflects a significant increase in capital during the past three years,” it said.

Citigroup was the largest of the four that failed the test — its tier one capital ratio level fell in the theoretical crash to 4.9 percent, below the fed’s 5.0 percent minimal threshold.

Citigroup’s actual tier one ratio was 11.7 percent in the third quarter of 2011, in the higher range of the 19.

But the tests found it particularly vulnerable to losses on home loans, commercial and industry financing, consumer loans and credit cards.

Citigroup in a statement defended its position and called on the Fed to make public more details of the tests.

But it also said that it would pull back on plans to boost its dividend payout.

“Citi remains among the best capitalized large banks in the world,” it said.

It said it would have passed the central bank’s test if it does not follow through with proposed capital actions — which the Federal Reserve rejected in the tests, Citi said.

“In light of the Federal Reserve’s actions, Citi will submit a revised Capital Plan to the Federal Reserve later this year, as required by the applicable regulations.”

The worst performance came from Ally, formerly the finance arm of General Motors known as GMAC: its tier one ratio fell to just 2.5 percent in the test from the actual 8.0 percent level reported in the third quarter of last year.

The company that has broadened from car loans to more general banking and insurance, is currently controlled by the US Treasury as a result of the government’s bailout of GM in 2009.

Echoing the grumbling from Citigroup and MetLife over the results, the American Bankers Association assailed the premises of the test as excessively severe.

“The banking industry is pleased that the overwhelming majority of institutions passed the Federal Reserve’s stress tests with flying colors,” ABA president Frank Keating said in a statement.

“The industry is now very well prepared for any challenging economic circumstances that could arise.”

“At the same time, we object to testing bank capital under theoretical conditions that are far more severe than even those seen during ‘the Great Recession.’”

“It unjustifiably prohibits some institutions from paying dividends to shareholders and could potentially impair their ability to raise capital and make loans.”