When I compare $TICK and $TICKC on TS, I see the divergence has been gradual over the last 3 or so months, not suddenly as I was expecting. My hypothesis is that NYSE Direct electronic trading is being counted as "regional" tick and as this volume increases so does the difference between $TICK and $TICKC. Before the hybrid system the regional volume was small enough that the two indicators were relatively close. Can anyone confirm/deny this?