Federal Reserve Chair Janet Yellen on Wednesday described stock market valuations as high and said the central bank was carefully monitoring their impact on financial stability. "I would highlight that equity market valuations at this point generally are quite high," Yellen said in conversation with Christine Lagarde, managing director of the International Monetary Fund, at an economics conference. Coupled with weak economic reports in the morning, her remarks drove stocks broadly lower in Wednesday trading. Yellen added, however, that the overall risks to financial stability are "moderated, not elevated" and she does not see the hallmarks of any bubbles. She...