Ban high frequency trading, ban instant transactions (put them on hold for some time before buying/selling (hours minmum, longer for larger quantities), make the held transactions public, and tax the profits on a time-owned scale.
This would turn "investments" into investments again... you really believe that company XY will do something good? Buy stocks and keep them for few years until they grow. Politican John Bobson dumps his stock of ZX company? Well, now we know before they actually get dumped, and can sell our stocks too.
Buying stocks of a company for 1.7 seconds and selling them back is not an 'investment' by any kind of proper definition.
This would turn "investments" into investments again... you really believe that company XY will do something good? Buy stocks and keep them for few years until they grow. Politican John Bobson dumps his stock of ZX company? Well, now we know before they actually get dumped, and can sell our stocks too.
Buying stocks of a company for 1.7 seconds and selling them back is not an 'investment' by any kind of proper definition.