Rounding out the top three is the iShares Short-Term Corporate Bond ETF (IGSB) at over $90 million in inflows YTD and the iShares National Muni Bond ETF (NYSEArca: MUB) at just over $80 million. MUB: seeks to track the investment results of the S&P National AMT-Free Municipal Bond IndexTM. While the Federal Reserve appears unflinching when it comes to its stance to keep interest rates low, what will it do if inflation starts to rise?