A passing vote would weigh on broad Eurozone markets and related ETFs like the iShares MSCI EMU ETF (NYSEArca: EZU) and SPDR EURO STOXX 50 (NYSEArca: FEZ). Both EZU and FEZ cover Eurozone member states and exclude United Kingdom and Switzerland exposure. Year-to-date, EZU is flat while FEZ dipped 1.6%.

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More aggressive currency traders can also target further weakness in the Eurozone through inverse ETF options if the vote passes. For instance, the ProShares Short Euro (NYSEArca: EUFX) is designed to provide 100% of the inverse, or opposite, return of the U.S. dollar price of the euro, on a daily basis and the ProShares UltraShort Euro (NYSEArca: EUO) provides 200% of the inverse return of the U.S. dollar price of the euro on a daily basis. The Market Vectors Double Short Euro ETN (NYSEArca: DRR) tracks the Double Short Euro Index, which also provides a -200% exposure to the euro.

U.K. markets are already feeling the pressure on the increased uncertainty. The iShares MSCI United Kingdom ETF’s (NYSEArca: EWU), the largest U.K. exchange traded fund listed in the U.S., is up 0.5% year-to-date. Although, the depressed pound sterling has helped currency-hedged options like the Deutsche X-Trackers MSCI United Kingdom Hedged Equity ETF (NYSEArca: DBUK) and the WisdomTree United Kingdom Hedged Equity Fund (NasdaqGM: DXPS), which rose 1.5% and 4.5%, respectively, year-to-date. While a Brexit vote would drag on the markets, investors may find some solace knowing that a depreciating GBP could help the currency-hedged ETFs outperform non-hedged options.

Related: Contrarian ETF Plays to Go Against the Grain

Investors can also hedge against the growing uncertainty with safe-haven bets. For instance, gold and related SPDR Gold Shares (NYSEArca: GLD) have been a go-to hedge during uncertain times. Billionaire investor George Soros, known as “the man who broke the Bank of England” for his multi-billion bet against the sterling, is also reportedly betting big on bearish investments, including gold.

U.S. Treasuries may also enjoy greater interest as a safe-haven play away from European assets. ETF investors may look to options like the iShares 20+ Year Treasury Bond ETF (NYSEArca: TLT) for more long-duration exposure and iShares 7-10 Year Treasury Bond ETF (NYSEArca: IEF) for intermediate-term exposure. Furthermore, U.S. government bonds could see increased foreign demand as British investors may find U.S. assets, like Treasury bonds, a more attractive store of wealth since the GBP would likely depreciate against the U.S. dollar in the fallout.