A US inflation report rattled global financial markets, boosting bets the Fed could get more aggressive with its belt-tightening campaign.  In a session of unnerving swings, the S&amp;P 500 failed to stay in the green after a sharp reversal from a 1.6% slide  https://t.co/xKcPzbNwvx  https://t.co/6UPbFnspPR