The market value of Europe's 20 largest banks has shrunk 40% since the beginning of 2020, amid economic turmoil caused by the coronavirus pandemic and fears about a second wave.

The combined market capitalization of the largest European lenders by assets was €466.07 billion as of July 31, 2020, down from €776.50 billion at Jan. 1, according to data compiled by S&P Global Market Intelligence.

Those headquartered in countries especially badly hit by COVID-19 have endured the steepest falls. U.K.-based HSBC Holdings PLC shed €64 billion in value, falling to €77 billion from €141 billion, while Lloyds Banking Group PLC and NatWest Group Plc lost more than half their market caps, and Barclays PLC almost half. Major French and Spanish banks BNP Paribas SA and Banco Santander, SA also experienced sharp drops.

The valuations of Swiss banks UBS Group AG and Credit Suisse Group AG, which have been buffered by strong wealth management businesses, fell less sharply than many other banks in the sample. UBS' market cap has overtaken that of Santander, Lloyds and Netherlands-based ING Groep NV since the beginning of the year.

U.K. Prime Minister Boris Johnson told BBC News in late July that there are signs of a "second wave" of coronavirus in Europe. Consultancy Oliver Wyman has estimated that European banks could face more than €800 billion of cumulative credit losses over the next three years if there is a second wave.

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All but one of the banks in the sample have seen declines in their price-to-tangible book values since Jan. 1, with most incurring drops of more than 20%. The metric measures a company's share price as a proportion of the book value of its assets, minus intangibles such as goodwill.

The outlier is Germany's Deutsche Bank AG, whose price-to-tangible book value increased by 4.05 percentage points between Jan. 1 and July 31. The bank has managed to cut costs and deliver strong investment bank revenues, and is also recovering from a share price that has declined consistently since the global financial crisis.