Amid a rally of epic proportions, Chinese stocks and the U.S.-listed exchange traded funds are once again hot stories. Few China ETFs have been hotter this year than small-cap funds.

Up an average of 51% this year, the Market Vectors ChinaAMC SME-ChiNext ETF (NYSEArca: CNXT) and the Deutsche X-trackers Harvest CSI 500 China A-Shares Small Cap Fund (NYSEArca: ASHS) are 2015’s two best non-leveraged ETFs to this point in the year.

The Guggenheim China Small Cap Index ETF (NYSEArca: HAO) has not exactly been a slouch, either. Following Wednesday’s 10.6% gain, which happened on volume that was more than 11 times the ETF’s trailing 90-day average, HAO is up 24.4% this year. [China ETFs are Getting Some Love]

HAO has closed higher in seven of the past eight trading sessions, hit a new 52-week high yesterday and is higher by 19.4% over the past week. Said another way, HAO’s move to the upside has been parabolic. It also caught many investors unprepared.

Wednesday’s price action and volume indicate that buyers probably stepped into HAO yesterday, but from the start of March through April 7, $3.8 million was pulled from the ETF. For the three-week period ending April 7, no money was added to or pulled from HAO, according to data.

Investors’ lack of appreciation for HAO is confounding. The ETF is neither new (it turned seven in January), nor small to the point of being off-putting (it has $240.1 million in assets under management). Additionally, HAO has a lengthy track record of outperforming China large-cap ETFs. Over the past three years, HAO has outperformed the iShares China Large-Cap ETF (NYSEArca: FXI) by 1,520 basis points while being nearly 200 basis points less volatile. [Proper Application of China ETFs]