This article originally appeared in The Financial Times.

The number of European banks in grave danger rose sharply last year and is now close to its 2013 level, despite extensive efforts by lenders to bolster balance sheets and profits, analysis by consultancy Bain shows.

The annual Bain review, which is being made public for the first time, examines about 110 European banks and scores them on profitability and balance sheet strength. The weakest face severe challenges on both fronts.

At the end of 2016, 31 were in the “weakest” category, a jump from 23 a year earlier and close to the 35 in the worst category in 2013.

Bain said that every European lender that failed in the past decade was in the weakest category before its failure, as were many of those that had to recapitalise during and after the eurozone financial crisis.

Already, four of the 31 weakest banks at the end of last year have ceased operating as standalone entities, the most high-profile being Spain’s Banco Popular, which was rescued by Santander in June.

“The fragile banks that have not acted effectively or that delayed taking action find themselves in a very difficult position,” said Joao Soares, author of the report.

He said he believes the number of banks in jeopardy has increased partly because the lenders that originally showed only problems in profitability developed issues with their balance sheets as losses mounted.

Banks were forced to reassess the value of their assets after regulators, led by the European Central Bank, increased scrutiny over how they were dealing with problem loans.

The ECB’s landmark review, carried out in 2014, when it assumed responsibility for supervising eurozone banks, also prompted some to raise capital, particularly in Italy, where nine failed.

Mr Soares said that, generally, capital raises mandated by regulators were not enough to shift banks out of the weakest category because many still had high levels of non-performing loans. Eleven Italian banks were in the weakest group at the end 2016.

But the new data also show an increase in the number of “winners”, those banks whose profitability and balance sheets were both strong. In 2016, 42 were in this category, up from 38 a year earlier and 33 in both 2013 and 2014.

“The European banking landscape is increasingly polarised,” said Mr Soares. “The winners have grown in number and have solidified their lead.”

The winners were being rewarded with average price to book ratios of 1.31, implying their share price gives them a value that is 1.31 times the value of their net assets. The weakest group had price to book values of just 0.31.

In its report, Bain wrote that “any bank at any point along the spectrum can return to good health . . . if the regulators, board and senior executive team have the commitment to carry out the hard decisions required over three to five years”.

It cited case studies of two banks that had moved from the weakest category in 2010 to the strongest now, by reducing their loans, cutting problem loans, increasing deposits, reducing wholesale funding and aggressively tackling costs.

Mr Soares said that Bain’s lawyers had advised against publishing the names of the banks in each category, even though the ranking is based on publicly available data. Instead, Bain lists the banks by nationality.

The weakest set includes 11 Italian banks, six Spanish, five German and two Greek. The strongest includes five each from Germany, France and the Netherlands and four from Sweden. Four UK banks were included in the survey, with one in the best category and none in the worst.