An improving trade account has provided major support to the US economy. Net exports contributed 1.7 percentage points to GDP growth of 2.2% in the year to the second quarter.

The consensus is sceptical of a similar positive impact from trade in the UK, despite sterling’s plunge. Independent forecasters expect net exports to contribute 0.3 percentage points to GDP growth in calendar 2008 and 0.4 pp in 2009, according to the Treasury’s monthly survey.

Recent trade figures suggest a larger boost. According to the July release issued this morning, export volumes of goods excluding oil and erratic items were 3.6% above their 2007 average in June / July versus a rise of just 0.2% in imports. Suppose total real exports and imports – including services – grow at these rates for the year as a whole. Net trade would then add 0.9 percentage points to calendar 2008 GDP expansion.

The ratio of export to import volumes in July was the highest since 2006 – see chart.