What's going on?

Germany�s DAX index is set to introduce tougher membership criteria and expand from 30 companies to 40, its operator Deutsche Boerse announced on Tuesday.

What does this mean?

This is the biggest-ever overhaul of the DAX � Germany�s stock market equivalent of the US�s Dow Jones Industrial Average and the UK�s FTSE 100 � and it has the Wirecard fiasco to blame. When Wirecard collapsed after failing to account for $2 billion in June, the DAX�s existing rules didn�t allow it to eject its first-ever bankrupt member right away. And Deutsche Boerse has no intention of letting that happen again: the index�s new criteria will now expect its members to publish quarterly statements and audited annual results � with a fast exit waiting for those that don�t release them on time.

Why should I care?

For markets: The DAX-chelor rose ceremony.

There could be some big benefits ahead for the newcomers� stocks � not least because they�ll get a bump when investment funds tracking the index are forced to buy into the companies. That�s no small thing: there�s currently $17 billion invested in exchange traded funds that track the DAX, a quarter of which will need to be invested in its 10 new names. As for which ones will make the grade: heavyweights like airplane manufacturer Airbus, fragrance producer Symrise, and ecommerce company Zalando all stand a good chance.

The bigger picture: That�ll do, Tesla.

Tesla knows a thing or two about the value of joining an index: the electric vehicle maker is all set to be added to the S&P 500 � which tracks the 500 biggest US companies � on December 21st, and the announcement alone was enough to send its stock up by 13%. It could have plenty further to go too: some of the biggest funds that need to own its shares haven�t bought in yet, and that�ll add up to roughly $8 billion worth � or 1.5% of the company�s current market value (tweet this).