There are also two smaller micro-cap ETFs that have round $65 million in assets, including the PowerShares Zacks Micro Cap Portfolio (NYSEArca: PZI) and Guggenheim Wilshire Micro-Cap ETF (NYSEArca: WMCR).

PZI tracks a smaller portfolio of 400 micro-cap stocks. The underlying index identifies micro-caps with the greatest potential to outperform passive benchmarks and other actively managed strategies. The enhanced indexing methodology makes the ETF come with a slightly higher 0.93% expense ratio. Top sector allocations include financials 28.7%, industrials 15.8% and consumer discretionary 14.9%. The fund has gained 3.6% year-to-date and is up 31.2% over the past year.

WMCR tracks the Wilshire US Micro-Cap Index, which currently holds around 966 stocks ranked below 2500 by market capitalization from the Wilshire 5000 index. Top sectors include financials 28.6%, health care 20.4% and information technology 13.7%. The Guggenheim ETF is the cheapest of the three, with a 0.53% expense ratio. WMCR has gained 8.2% year-to-date and is up 40.5% over the past year.

For more information on micro capitalization funds, visit our micro-cap category.

Max Chen contributed to this article.

Full disclosure: Tom Lydon’s clients own shares of IWC.