iShares MBS ETF is a company in the U.S. stock market and it is a holding in 7 U.S.-traded ETFs. MBB has around 1.1M shares in the U.S. ETF market. The largest ETF holder of MBB is the iShares Yield Optimized Bond ETF (BYLD), with approximately 521.43K shares. Investors may also find of interest that the ETF with the largest allocation to MBB stock is IQ Enhanced Core Plus Bond U.S. ETF (AGGP), with a portfolio weight of 30.77%. On average, U.S. ETFs allocate 13.49% of MBB to their portfolios.