Manipulation

This is a multifaceted complicated issue. There is no accurate way to know exactly what is going on in this area. Even the SEC can't really get a grip on this.

Here is why.

The trades can be done from anywhere and might have underlying derivatives. Situations can dictate whether it's legal or illegal.

Every trade would have to be looked at, the MM that executed the trade, the broker that gave the order to the MM, and the underlying client that gave the order to the broker.  That client might be a corporate client. In that corporation there may be several people with the authority to sell or buy equities. There maybe a 3rd party working for the corporation dictating trades, such as a fund mgr.

These trades could originate in a country other than the US. I could go on and on and on.