Doubling an investment in five years is an excellent result by just about any investor's standard. While the S&P/ASX 200 Index (ASX: XJO) is up just 45% over five years, 3 ASX financials ETFs have doubled over the period.

Which exchange-traded funds (ETFs) are they? And what might the next 5 years look like? 

Let's see.

VanEck Australian Banks ETF (ASX: MVB)

At the time of writing, the VanEck Australian Banks ETF is up 100.53% over the past five years. For an annual management fee of 0.28%, the MVB ETF comprises seven Australian banks, including the big four banks. Each of the big four banks represents approximately 20% of the fund, while Macquarie Group Ltd (ASX: MQG) has a 17% allocation.

The ASX banking sector has performed incredibly well over the past few years. In particular, Commonwealth Bank of Australia (ASX: CBA) has defied analyst expectations and risen 172% in five years. Today, it reached another new all-time high of $192.

However, analysts and fund managers continue to warn that the ASX banking sector is overvalued. Macquarie currently has 2 neutral ratings and 2 underperform ratings on the big four banks. This suggests that the next five years are unlikely to match the past five years.

BetaShares Australian Financials Sector ETF (ASX: QFN)

The BetaShares Australian Financials Sector ETF is up 108.05% over the past 5 years, at the time of writing. For an annual management fee of 0.34%, the QFN ETF tracks the largest ASX financials stocks (including the big four banks), as well as insurance companies. 

With 28 holdings, it is more diversified than the MVB ETF. However, with 70% of the ETF invested in the big four banks, its forward returns are likely to be correlated with those of the MVB ETF.

Betashares Global Banks Currency Hedged ETF (ASX: BNKS)

The Betashares Global Banks Currency Hedged ETF is up 103.36% over 5 years. For an annual management expense of 0.47%, investors gain exposure to the world's largest banks outside of Australia in a single trade. 

This ETF is very well diversified, with 60 holdings. As of 30 May, its largest holdings were JP Morgan & Chase (7.6%), Bank of America (7.3%), and Wells Fargo (6.1%). 

Yesterday, I discussed JP Morgan relative to CBA shares. As explained, JP Morgan is arguably a much higher-quality bank and is trading on a price-to-earnings (P/E) multiple that is less than half of CBA (14 vs 33). By preferencing Australian banks (and Australian bank ETFs) in spite of high valuations, ASX investors are demonstrating a high level of home bias. In the case of ASX bank stocks, this could dramatically impact forward returns.

Based on valuation, the BNKS ETF is likely to outperform the MVB ETF and the QFN ETF over the next 5 years. 

One disadvantage of investing in foreign stocks is currency risk. However, the BNKS ETF is hedged to Australian dollars, reducing this risk. 

Investors looking for banking exposure or ASX financials ETFs over the next 5 years might like to consider the BNKS ETF.