The Paris-based Organisation for Economic Cooperation and Development said its leading indicator covering 33 member countries was unchanged for the sixth month in a row at 100.6, above its long-term average of 100.
The indicator, designed to flag turning points in the economic cycle, pointed to stable growth momentum in the OECD area as a whole.
In the United States, growth momentum was above a long-term average at 100.6, its third consecutive month of improvement, while Britain's economy was above trend at 101.13 and improving for the fourth consecutive month.
Italy's growth momentum was improving strongly to 101.74 while the reading for France was stable at 100.33, with a slight improvement from the previous month.
However, growth momentum was above average but flagging in Japan with a reading of 100.40, possibly due to a one-off tax increase. In Germany the reading was 100.48, its fifth consecutive month of decline.
Among major developing economies, growth momentum was slowing or near stable with readings slightly below 100.
China's growth prospects had improved slightly to 99.25 from 99.10 the previous month, while India showed tentative signs of stronger momentum with a reading of 98.22.