Exchange-traded funds are simple, cheap and hugely popular. Their goal is to invest in or replicate the performance of a basket of assets or index. Rather than pay a money manager hefty fees to actively pick and choose what the fund holds, ETFs have been “passive” investments, automatically buying and selling based on the benchmark being tracked. Now a hybrid approach known as active ETFs that seek to keep the advantages of the format while outperforming benchmarks is gaining adherents, thanks i