NEW YORK ( ETF Expert) -- Bullish commentators have been busy admonishing those who might be cautious. Their reasoning? Long-term investors should focus on the signs that point to stable economic growth in the U.S., a recovery in China as well as unwavering stimulus by the Federal Reserve.Besides, with Treasuries offering more risk than reward, where else are you going to realize a worthwhile return on your money? However, a number of Fed policymakers recently expressed reservations about the amount and the duration of the central bank's bond-buying program. In other words, current monetary policy that artificially depresses interest rates may not continue indefinitely. Moreover, the idea that economic growth in the U.S. will demonstrate ongoing signs of stability and/or improvement discounts the high probability of a sequestration drag; indeed, automatic spending cuts are likely to hamper job growth, curb consumer spending and crimp investor confidence. Between the finger-pointing in Washington and the release of the Fed minutes Wednesday, the S&P 500 logged one of its worst performances of the year (-1.25%). At least in the immediate term, bulls and bears both appear to be growing more anxious about ownership of riskier assets. Was the Wednesday session merely a one-day bout of profit-taking? Or did the move to the downside represent a tipping point for future sell-offs? I have listed three ETF indicators for evaluating the current investing environment. 1. ProShares UltraShort Euro ( EUO). Eager risk-takers have been climbing aboard the "Europe Express," determining that central bank assurances to do whatever it takes to save the euro signaled an end to Europe's debt crisis. I'm not so sure. Greeks are currently marching against austerity as I type, Spain's recession is deepening and Italy's upcoming election could upset the proverbial apple cart. Equally worthy of note, the Fed may or may not scale back on its bond buying. That might bolster the greenback. And Spain may find itself asking for a formal bailout, which would depress the euro.