US Federal Reserve chair highlights concerns over ultra-low interest rates

Janet Yellen discussed potential dangers with IMF's Christine Lagarde amid fears that near-zero borrowing costs may distort markets and create bubbles

Janet Yellen, chair of the US Federal Reserve, has highlighted the risks of ultra-low interest rates for financial stability, warning investors that share valuations are "quite high".

At a seminar in Washington, Yellen was asked by International Monetary Fund (IMF) managing director Christine Lagarde about fears that near-zero borrowing costs distort markets and create bubbles.

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