A measure of future U.S. economic growth edged lower in the latest week, while the annualized growth rate also sagged, a research group said on Friday.

The Economic Cycle Research Institute, a New York-based independent forecasting group, said its Weekly Leading Index slipped to 121.3 in the week ended Dec 16 from 122.3 the previous week.

The index's annualized growth rate dipped to minus 7.7 percent from minus 7.5 percent a week earlier.