Shares of the Global X FTSE Greece 20 ETF (NYSEArca: GREK), the lone exchange traded fund tracking stocks in the problematic Eurozone nation, are off 15% today on volume that is already nearly triple the daily average after the government there imposed capital controls and proposed plans for a national referendum Tuesday as the country inches closer to the expiration of its current bailout program.

Adding to the calamity in Greece, regulators there closed the country’s equity market today, putting the burden of price discovery for Greek stocks, at least in the U.S., on GREK. The burden is heavy as the $369.7 million ETF is heading toward its worst intraday performance since coming to market in December 2011 and is Monday’s worst-performing ETF on a percentage basis by a wide margin. [Greece ETF Tries to Elude Debt Fears]

There is precedent for U.S.-listed ETFs tracking foreign markets acting as price discovery tools when those markets are closed due to local calamity, but the precedent is not positive.

“While a minor plot in the larger Greek saga, the ETFs have captivated investors in recent months as they looked to express views on the future of its markets. When Egypt’s exchange was shut for two months during the Arab Spring uprising in 2011, investors bid up Market Vectors Egypt Index ETF (NYSEArca: EGPT) only to see it plunge when the exchange reopened,” report Lu Wang and Oliver Renick for Bloomberg.

Capital controls are having an adverse impact on GREK as well. The government’s gambit to impose a 60-euro withdrawal limit from Greek banks could drive a run on banks and is bad news for GREK, an ETF that allocates nearly a quarter of its weight to financial services stocks. That is more than 700 basis points than the ETF’s consumer discretionary weight, its second-largest sector allocation.