A measure of future U.S. economic growth edged up last week to hold a more than six-month high, while the annualized growth rate also improved, 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 its highest level since mid-August at 124.3 in the week ended March 2 from a downwardly revised 124.1 the previous week. 

That was originally reported as 124.2. 

The index's annualized growth rate gained to minus 2.6 percent from minus 3.0 percent.