Yellen tone suggests choppiness for markets this week

NEW YORK: US stock investors have been enjoying an extended period of low volatility and steady gains, but with the Federal Reserve on track to raise interest rates this year and major indexes near records, the market could get a bit choppier in coming weeks.

Fed chair Janet Yellen on Friday said she expected the US central bank to raise rates in 2015, though the process was expected to be gradual, with the timing of the first hike dependent on the strength of economic data.