"The $4.4 trillion asset manager is seeking approval for a Total Corporate Bond ETF, which would use the “ETF-of-ETFs” structure to buy other debt funds sold by the company, rather than individual bonds, according to regulatory filings"
https://www.bloomberg.com/news/articles/2017-08-23/vanguard-jumps-aboard-etf-of-etfs-bandwagon-the-vanguard-way?utm_source=yahoo&utm_medium=bd&utm_campaign=he adline&cmpId=yhoo.headline&yptr=yahoo
https://www.bloomberg.com/news/articles/2017-08-23/vanguard-jumps-aboard-etf-of-etfs-bandwagon-the-vanguard-way?utm_source=yahoo&utm_medium=bd&utm_campaign=he adline&cmpId=yhoo.headline&yptr=yahoo