The massive 50,000+ block of S&P 500 e-mini futures came as Angela Merkel threw a mini bombshell surprisingly stating that tonight's summit press conference was canceled as "talks on growth accord continuing" according to bloomberg. That was enough, according to some, to see a significant squeeze of short positions in the EUR/USD, up towards 1.2450, although IFR Markets reports that "core positions remain in place."
The excuse to push risk higher was also that there are renewed hopes for more plausible EU political action. Another suspicious driver was based on rumours that Spain and Italy may receive bailout money. Reuters is out with a headline also, saying that some major announcement from the EU Summit is expected, and that is the reason Merkel canceled her presser, they say.