WASHINGTON, DC: US consumer spending was slow in 2015, but a new report has shown that everyday spending in 15 US cities increased +2.3% year-on-year in December, with younger consumers and those on lower incomes fuelling the rise.

These are the headline findings in the Local Consumer Commerce Index (LCCI), a new measure of the monthly year-over-year growth rate of everyday debit and credit card spending in the US from JPMorgan Chase Institute.

When constructing its new index, the global think tank drew on 14bn anonymised credit and debit card transactions from more than 50m Chase customers in Atlanta, Chicago, Columbus, Dallas, Denver, Detroit, Houston, Miami, Los Angeles, New York, Phoenix, Portland in Oregon, San Diego, San Francisco and Seattle.

These 15 metropolitan areas effectively accounted for almost a third (32%) of retail sales nationwide and the report found that local consumer commerce growth varied considerably across them.

While all of them experienced positive year-on-year growth in December – the first time this has happened since January 2015 – the LCCI revealed that Atlanta saw the fastest growth of +5.1%.

Los Angeles (+4%) grew the fastest among the five largest metro areas – the others being New York, Chicago, Dallas and Houston – and, at just +0.3%, Houston recorded the lowest growth of all the 15 metropolitan areas covered in the study.

Meanwhile, among mid-sized cities, local consumer commerce in December 2015 grew the least in San Francisco (+1.8%), while growth in Miami was only marginally higher at +1.9%.

Turning to the five smallest metro areas in the study, local consumer spending grew the fastest in Portland (+4.4%) whereas Seattle had the slowest local consumer commerce growth among these smaller cities at +2.3%.

The report went on to show that consumers aged under 25 contributed 1 percentage point to growth, which it said was "a strong contribution given their relatively low share of spending and the overall slowdown in spending".

By contrast, consumers aged 65 contributed just 0.6 percentage points to growth in December, although this was the largest amount by this group since January 2015.

Finally, the report also showed that consumers in the lowest 20% income bracket (who logically could include many younger consumers) increased their spending by 1.3 percentage points at the same time as their counterparts in the top quintile, by income, cut 0.4 percentage points from growth.

Data sourced from JPMorgan Chase Institute; additional content by Warc staff