The sheer magnitude of it is what makes it seem like a pump and dump, however. The mechanics are broadly similar: send a signal that should cause people to bid

The sheer magnitude of it is what makes it seem like a pump and dump, however. The mechanics are broadly similar: send a signal that should cause people to bid up securities you own, then drop the bottom out by selling when the price goes up enough. I’m not saying it’s illegal per se, but financial misdeeds don’t tend to get punished in the US, unless the victims are wealthy enough. See, for instance, the global financial crisis of 2008 vs Bernie Madoff.