[dcolkitt]

An internalizer must match displayed NBBO at the exchanges. If it can’t, it has to route to the exchange, pay exchange fees, and on top of that still pay for the order flow.

Normally internalizers have no problem competing with spreads on the exchanges, because retail flow is much less toxic than the sophisticated traders in the public venues. But with GME, the retail investors are running the show.

Therefore it no longer makes sense for internalizers to pay for this order flow.