The party's over...for now. Stocks' six-day winning streak came to an end in Friday's session as the Dow, Nasdaq and S&P all closed lower with minor losses. Twitter shares plunged after one Wall Street analyst downgraded the stock. And late in the day, regulators said they're considering exempting some complex securities from the newly approved Volcker rule after feeling the heat from community banks. Jeanne Yurman reports.