A measure of future U.S. economic growth edged up last week, while the annualized growth rate improved but still remained in negative territory, a research group said on Friday.

The Economic Cycle Research Institute, a New York-based  independent forecasting group, said its Weekly Leading Index  rose to 122.8 in the week ended Aug 10 from 122.5 the previous week. 

The index's annualized growth rate improved to minus 0.6 percent from minus 1.1 percent a week earlier.