Dow has worst day in six months amid concerns from Ukraine, Portugal and Argentina. U.S. economic data and earnings weighed too.» Read More
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When it comes to what investors think will spoil the 6-year-old bull market, most point directly to the Federal Reserve.
Argentina is almost certainly headed for a technical default of its bond-payment obligations at 12:01 Thursday morning.
Corporate America may have another tax-avoidance trick up its sleeve.