Treasury ETFs have been under the gun since the end of April on rising yields. Now, the iShares 20+ Year Treasury Bond Fund (NYSEArca: TLT) is testing a key technical resistance line as investors await testimony from Federal Reserve Chairman Ben Bernanke and CPI data this week.

Bernanke is schedule to testify to Congress on Wednesday and Thursday about the U.S. economy and monetary policy. Investors will be looking for any color on the Fed possibly tapering its bond purchases. Last week, Bernanke said the central bank may keep interest rates near zero even if the unemployment rate falls to its target. [Treasury ETFs Rebound on Bernanke, Lower Yields]

Before Bernanke, June CPI data will be released Tuesday. [Rising Rates and Low Inflation a Toxic Mix For TIPS ETFs]

“In the U.S. attention will like be focused on Ben Bernanke’s mid-year testimony to congressional committees on Wednesday and Thursday. Judging from his recent statements he will be at pains to reassure the public that, even with a timetable for the phase-out of bond purchases, monetary policy will remain very accommodative for a long time to come,” said David Kelly, chief global strategist at JP Moran Funds.

Meanwhile, the CPI data should contain the most important numbers of the week, he added.

“Our forecasts, which show a slightly milder increase than consensus expectations, nevertheless indicate a stabilization in inflation after recent declines,” Kelly wrote in a weekly outlook. “Going forward, there is evidence that gradually tightening labor markets are boosting wage growth while a recent spike in crude oil prices appears to be leading to a surge in recently quiescent gasoline prices. Overall, despite concerns expressed by some Federal Reserve officials, there is little evidence that inflation is sliding towards deflation.”