The exchanges create an orderly secondary market between investors and market makers. The market makers post quotes and execute investor transactions, often creating or redeeming ETF shares in the primary market with the ETF issuers. Source: Vanguard.
There are currently more than 50 Vanguard exchange-traded funds, which are traded, like any other shares, on the U.S. stock exchanges, such as the New York Stock Exchange (NYSE) or Nasdaq. Their underlying indexes cover both individual sectors, such as materials and energy, and domestic and international indexes.
Log into your Vanguard account online and look for the “Options if I leave my employer” link. Follow the instructions from there to initiate your rollover.