Leading the charge was State Street, with the SPDR Barclays Capital International Treasury Bond ETF (NYSEArca:BWX) and the SPDR DB International Government Inflation-Protected Bond ETF (NYSEArca:WIP) as the first international bond and international inflation-protected bond ETFs. For an asset class that plays such an integral role in global capital markets and in investorsâ portfolios, the options available to investors prior to 2011 were mostly broad and U.S. focused. In the real world of ETFs, that means that providing exposure to niche areas requires high levels of optimization, which, in turn, can lead to tracking error.