The European exchange-traded fund (ETF) industry has truly written a growth story over the last 16 years. The steadily increasing assets under management have led to a number of discussions about the impact of the ETF industry on the markets. Some market observers have raised concerns about the markets covered by ETFs, especially in the bond segment, since a number of bonds—even though they are in a benchmark— do not have sufficient liquidity to be traded in huge quantities. Even though the liquidity issue is valid, ETF promoters in Europe have found ways to overcome this limitation with so-called optimized