While individual stock exchanges compete against each other to get maximum transaction volume, stock markets as a whole may be facing competitive threats on two fronts.
Dark Pools
Dark pools, which are private exchanges or forums for securities trading and operate within private groups, are posing a challenge to public stock markets. Though their legal validity is subject to local regulations, they are gaining popularity as participants save big on transaction fees.
Blockchain Ventures
Amid the rising popularity of blockchains, many crypto exchanges have emerged. Such exchanges are venues for trading cryptocurrencies and derivatives associated with that asset class. Though their popularity remains limited, they pose a threat to the traditional stock market model by automating a bulk of the work done by various stock market participants and by offering zero- to low-cost services.