FRANKFURT AM MAIN: Germany's blue-chip DAX 30 index will grow by 10 companies and tighten entry rules following criticism over the spectacular collapse of former member Wirecard, stock exchange operator Deutsche Boerse said, last week.

The changes, which come into effect in September 2021, will raise the flagship index from 30 to 40 members, and require new entrants to have made an operating profit over the last years. They will also be required to publish their audited financial reports.

"The comprehensive changes in the index rules were decided to increase the quality of the DAX indices and to align them with international standards," Deutsche Boerse said in a statement.

"This is a historic milestone", said independent analyst Timo Emden, and one that is "long overdue" for the Frankfurt index, which was launched in 1988 as Germany's answer to the Dow Jones Industrial Average. The DAX suffered a blow to its reputation after digital payments provider Wirecard in June admitted to a 1.9 billion euro hole in its accounts, and top executives were arrested on fraud suspicions soon after.