Yes and no; with maturities and new purchases, yes, new bonds (at revised rates and prices) will be purchased, and these will not get the same benefit from lowered rates. But, XBB is a $6.4B fund, and its portfolio securities may not turn over as much as one expects. XBB buys can be matched with sells, and it is only when a mismatch occurs does the market maker need to be active in the portfolio. Thus, we would expect 'most' of the portfolio to still benefit from rate moves (assuming rates decline!). Nothing to write home about, but the fund is at least now UP on the year. Its average duration is 7.4 years, so it should have decent leverage to rates with that maturity.
5i Research Answer: