By Max Colchester 

LONDON--No major banks flunked Europe's stress test, but several big lenders suffered close shaves.

The tests estimated how banks' capital ratios would hold up in a deteriorating economy. Banks whose ratios sink below 5.5% of their risk-adjusted assets needed to come up with additional capital.

Of the 123 banks that the European Banking Authority tested, 24 fell below that threshold. (An additional bank failed a similar, overlapping European Central Bank exercise.)

But a total of 14 banks came closer to failing. They passed the test with capital ratios between 5.5% and 7%. Those relatively near misses mean the banks could face pressure to further bolster their balance sheets to avoid regulatory and market questions about their health.

In Italy, where nine banks failed the tests, some of the country's top lenders squeaked by. Mediobanca SpA, a leading investment bank, logged a capital ratio of 6.2% under the worst-case scenario. UniCredit SpA, Italy's largest bank by most measures, posted a 6.8% ratio.

In the U.K., the two giant lenders that were bailed out by taxpayers during the crisis also passed with less than flattering results. Royal Bank of Scotland Group PLC and Lloyds Banking Group PLC scored 6.7% and 6.2% respectively. Ireland's Allied Irish Banks PLC and the Netherlands' SNS Bank NV also narrowly passed.

Only one small German bank failed the test, a surprisingly strong performance for a country whose lenders have been the target of investor angst. But six banks--mostly small regional lenders--came in below the 7% level, including HSH Nordbank AG.

It is unclear what the ramifications of a close pass will be. Lloyds, which is 25% owned by the British government, is hoping to resume paying dividends after the stress tests. Some investors worry the underwhelming results may dull regulators desire to sign off on a handout to shareholders. A Lloyds spokesman said the bank welcomed the results. RBS issued a statement saying it "continues to make good progress in improving" its capital ratios.

Mediobanca said that it passed the exercise. UniCredit didn't immediately comment. SNS Bank said the test showed its resilience even under "severe methodological restrictions." HSH Nordbank didn't immediately return calls for comment. Allied Irish Banks said that "comparisons are only valid when done on a consistent basis." The bank said that when taking into consideration its restructuring plan its ratio rises to 10.26%.

Analysts said that the reason several big banks passed by relatively narrow margins was that the EBA's tests didn't necessarily take into account actions taken this year. RBS and Lloyds, for example, have been heavily restructuring their balance sheet since then, including by selling business lines.

RBS and Lloyds will undergo a further stress test by the Bank of England, which will present its results on Dec. 16. The central bank said that the "EBA results should not be interpreted as indicative of the U.K. results." This is in part because the Bank of England will take into consideration management actions during its modeled economic collapse.

Write to Max Colchester at max.colchester@wsj.com

Subscribe to WSJ: http://online.wsj.com?mod=djnwires