Top bond fund manager Jeffrey Gundlach says the “the moment of truth for this year’s investments” will come at the end of June, when the Federal Reserve’s second round of quantitative easing comes to an end. “QE2 was obviously designed to help the economy,” Gundlach tells CNBC. “If it [QE2] helps the economy and it helps stocks and it helps commodities, ergo when you take it away you might go in the other direction, which I think will be the case.” Gundlach also notes that the Fed’s plan to buy up Treasury bonds has actually resulted in interest rates rising, because it stokes inflation fears, and says the U.S. must attack its huge federal deficit soon, though it will likely be a negative for the economy. He also says the fact that big bond managers like PIMCO have shunned Treasury bonds means there’s a lot of dry powder waiting on the sidelines for a bond rally.