VIOO seeks to replicate a benchmark which offers exposure to small cap firms in the U.S. equity market. The investment thesis behind small caps is that these firms are likely to provide strong growth prospects to a portfolio and should have a much easier time growing then their large cap counterparts. However, these securities are extremely volatile and can experience large losses or gains in a very short period of time. Despite their volatility, these products should probably be in every investors' portfolio as they tend to move somewhat independently of large caps and can be a better 'pure play' on the American economy. This particular ETF, since it focuses on both value and growth securities, could provide more of a diversified play than products that just focus on 'growth' or 'value' securities within this segment. Thanks to this broad focus, VIOO has a large number of securities-- close to 600 in total-- and does a great job of dividing up assets among the components as no one company makes up more than 80 basis points of total assets. Thanks to this high level of diversification and VIOO's low expense ratio, the fund could make for a quality addition to portfolios of investors who are looking for small cap exposure and do not have a preference in terms of value or growth equities.