I don't have handy documented examples of private individuals successfully manipulating the market with news, but supposedly during the '07 crash the banks had the rating agencies keep the ratings for the collapsing subprime MBS's dishonestly high long enough for the banks to get out of their subprime MBS positions. Not exactly the same but very similar.

https://en.wikipedia.org/wiki/Subprime_mortgage_crisis#Inacc...