The product added 15.85 per cent in the period. It surged 10.9 per cent on 30 April, the day Chinese company China Mobile agreed to buy a 12 per cent stake in Taiwan-based Far EasTone.
The iShares MSCI South Korea ETF was the second best performer, rallying 14.64 per cent.
The iShares S&P SmallCap 600 ETF, which holds many small-cap United States equities, advanced 11.06 per cent for third place.
Developed market, Chinese and defensive stocks were among the weaker performers.
The iShares MSCI EAFE (European, Australasian and Far Eastern markets), iShares FTSE/Xinhua China 25 and iShares S&P 500 ETFs gained 6.66 per cent, 5.91 per cent and 3.60 per cent in April, respectively.
The SPDR S&P/ASX 200 ETF, which tracks the benchmark S&P/ASX 200 Index, gained 5.55 per cent. The SPDR S&P/ASX 200 Listed Property ETF gained 4.01 per cent.
The iShares Global Consumer Staples, iShares S&P Global Telecommunications and iShares S&P Global Healthcare ETFs lost value.
The ETF Securities Physical Gold, which tracks the price of the precious metal, slipped 7.55 per cent in the month.
