VWOB seeks to track the performance of a benchmark index that measures the investment return of U.S. dollar-denominated bonds issued by governments and government-related issuers in emerging market countries. One Vanguard offering is the Vanguard Emerging Markets Government Bond Index Fund ETF Shares (VWOB). "In addition to the attractive yield, many emerging-markets central banks have proactively raised real rates (interest rates adjusted for inflation) at a much faster pace to their developed-markets peers, as many emerging-markets central banks have been less willing to test if current inflation will prove transitory," Morningstar added.