[nl]

> How, uh, do you do this legally?

It's simple to have information about the future in entirely legal ways. Usually the future information is available, just unequally distributed.

The best example of this is the movie "The Big Short" where it the information about the upcoming crash of subprime-backed bonds just required people to bother reading large amounts of bond composition documents. Only 3 groups really did this.

Another good examples is how some funds pay for logistics intelligence (via satellite reconnaissance, customs declarations etc) to forecast sales figures.