An anonymous reader writes "Billionaire Mark Cuban talks in an interview with the Wall Street Journal about how he thinks high-frequency trading can be quite damaging to stock markets. He goes so far as to call high-frequency traders the 'ultimate hackers.' He says, 'They're running software programs that have one goal, and that's to exploit the trading systems as early and often as possible. As someone who wrote software for eight years and who keeps up very closely with the technology world, that scared the hell out of me. The only certainty in the software world is that there is no such thing as bug-free software. When software programs are trying to outsmart other software programs and hack the world's trading platforms, that is a recipe for disaster. ... How many times an hour are there failures across individual equities around the world because of software running algorithms battling each other for supremacy to make a profitable trade? We have no idea. It's not a question of if or when we have meltdowns, it's just a question of how big and where. It's straight out of War Games. And that's before we even get to the possibility of nefarious or sovereign hackers getting involved.'"