Stock and commodities exchange traded funds were under pressure Friday as the dollar strengthened against its major rivals. In recent years, a rising dollar has usually been a bad sign for riskier assets.

Currency ETFs that track the dollar and the euro are back at a key test of their 50-day moving average.

Investors are closely watching credit markets in Greece, Ireland and other troubled countries in the Eurozone. CurrencyShares Euro Trust (NYSEArca: FXE), which tracks the movement of the euro versus the dollar, dropped more than 1% on Friday.

“The dollar is now moving higher against the euro,” writes Jeff Macke at Yahoo Finance’s Breakout. “The dollar hasn’t ‘broken out’ versus the euro and stocks haven’t ‘broken down’ below support. But a rising dollar and falling stocks are looking more likely every day, and it’s putting pressure on assets across the board.”