Electronics and biotech ETFs were the two biggest winners in the first half of 2017, according to an analysis from TrackInsight.

ETFs tracking technology and electronics saw the biggest inflows of any sector, attracting more than €4 billion. Inflows were particularly pronounced in the US.

Biotechnology ETFs were the best performing segment with ETFs falling under this umbrella averaging returns of 11.2%. Leisure - a broad and little-used category that includes food services, travel and hotels - was the second best performing sector delivering returns of 10.8%.

In relative terms, chemical ETFs were the biggest winners, seeing their AUM increase 90% over six months. As the segment is quite small, however, the large percentage change translates to only €123 million.

The biggest losers so far this year have been ETFs linked to basic materials stocks - ore, timber, chemicals, etc. - which saw outflows of nearly €400m. This asset class, which supplies building stock for the real economy, is highly cyclical and correlates with commodity prices.

The worst performing segment by a large margin was natural gas, which saw performance fall off a cliff, declining by 23%. Relatedly, energy as a sector declined 17%. The poor performance of these ETFs is related to the lower prices of oil.