CHICAGO: The US has retaken its position as the top ecommerce market in the world after an improving economy helped the nation deliver 15% ecommerce growth in 2014, a new global study has calculated.

After ranking third behind China and Japan in 2013, US ecommerce reclaimed top spot last year because it best met the "online market attractiveness score" contained within the 2015 Global Retail E-Commerce Index.

Produced by management consultants AT Kearney, the Index is a ranking of the top 30 countries based on nine variables and is aimed at helping retailers to identify market investment opportunities.

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AT Kearney said these variables include select macroeconomic factors as well as those that examine consumer adoption of technology, shopping behaviour, infrastructure and retail-specific activities.

According to the analysis, China's slowing rate of ecommerce growth pushed the nation into second place and the report said a large part of its future growth will be driven by smaller tier 3 and tier 4 cities.

However, "there are questions about infrastructure investment, logistics support (a key to retail ecommerce growth), and consumer spending" in the country, the report said.

Japan (#4), which was ranked second in last year's Index, has also been overtaken by the UK (#3). Some other ranked European countries include Germany (#5), France (#6), Belgium (#9), which jumped 15 places, Denmark (#15, up 13 places) and Spain (#18), which entered the rankings for the first time.

Mexico (#17) was also a new entry this year, after posting an "impressive performance", but, elsewhere in the region, Brazil (#21) dropped 13 places from 2013 and Argentina (#29) fell a steep 17 spots owing to their "slowing macroeconomics".

Despite declines in China, Japan and a few other countries in Asia-Pacific – for example, South Korea (#7, -2), Australia (#10, -1), Singapore (#14, -3) – the report still expected the region to become the world's largest for ecommerce.

Commenting on the report, co-author Mike Moriarty, said: "Both brick-and-mortar leaders and major pure-play online retailers are learning that the future of the industry is not merely online, but rather in creative omnichannel offerings that link online and physical shopping."

Data sourced from A.T. Kearney; additional content by Warc staff