> but I've never understood what the employee gets out of it They may get money? Some of these companies have valuation in hundreds of billions, and a small b

> but I've never understood what the employee gets out of it They may get money? Some of these companies have valuation in hundreds of billions, and a small bit of news can nudge that +/- 0.5-2% or more which could be a couple billions dollars. If you own just 0.1% of the stock, that would be several $m opportunity . So, paying your informer, say, $100K or something, sounds reasonable, if you can execute it properly, even accounting for fake informers.