The VIPERs are part of an index fund class that monitors capitalization and investment styles of the U.S. stock markets, using benchmarks set up by Morgan Stanley Capital International (MSCI).
The move brings the total number of VIPERs offered by Vanguard to 16 with an additional 6 expected to launch later this year. Vanguard looks to sell investors shares based on their low expense ratios relative to other funds in their class.