Losses are modest in Paris , London , Sydney and Melbourne . CNN 's Tom Cohen , Kyung Lah and Mark Meinero contributed to this report . Investors are weighing both the downgrade and the European debt crisis . G7 leaders say they are committed to ' ` ` all necessary measures '' U.S. stock futures tumble around 1.7 % in early electronic trading .
Losses are modest in Paris , London , Sydney and Melbourne . Investors are weighing both the downgrade and the European debt crisis . G7 leaders say they are committed to ' ` ` all necessary measures '' U.S. stock futures tumble around 1.7 % in early electronic trading .