The Globe and Mail reports in its Wednesday edition that most exchange-traded funds are quite transparent, but there are the occasional outliers -- funds that perform much better or worse than people expected. The Globe's Gordon Pape highlights RBC Canadian Bank Yield Index ETF (RBNK). At $50.99, its annual payout is $1.56 for a yield of 3.1 per cent. You may wonder how an ETF that invests only in six banks can outperform the financials subindex and funds such as the BMO Equal Weight Banks Index ETF (ZEB). The answer is asset mix. Whereas the BMO fund equally divides its holdings among the Big Six banks, this one makes bets on which will perform best. At present, Bank of Montreal is in the top position at 26.1 per cent, followed closely by Bank of Nova Scotia at 25.1 per cent. They've both done well, with BMO ahead about 40 per cent year-to-date, while Scotiabank has added about 21 per cent. Ironically, fund sponsor Royal Bank Of Canada is close to the bottom of the list, with a weighting of just 8.7 per cent. It has actually performed better than the low weighting would suggest, with a year-to-date gain of about 28 per cent. The fund was launched in October, 2017, and has assets under management of $522-million.