Seventeen of Europe's 20 biggest insurers saw their market capitalization increase on a percentage basis as markets rebounded in the second quarter following a brutal first three months of the year, according to an S&P Global Market Intelligence analysis.

Germany's Munich Re recorded the biggest quarterly increase at 25.7%. The top five remains unchanged, led by Allianz Group, although the gap between second-place Zurich Insurance Group AG and third-place Axa SA narrowed as the Swiss insurer's market cap dropped by 2.1% while Axa's rose 17.9%.

Italy's Generali climbed to sixth place after seeing its market cap grow 9.0% to €21.21 billion, while Swiss Re AG dropped a spot to seventh as its market cap fell 2.0% in local-currency terms. The third decliner, Norway's Gjensidige Forsikring ASA, saw its market cap dip 0.5%.

CNP Assurances SA and Bâloise Holding AG are new entries to the top 20, with market caps of €7.03 billion and €6.07 billion, respectively.