Later in the day, Brown meets with another analyst to discuss the current fixed-income environment. This second analyst believes fixed-income markets are about to enter a period of high uncertainty. This analyst also expects a flight to quality and a bullish flattening of the yield curve. He recommends Brown adjust the fund's exposure through the purchase and sale of option-free default-risk-free bonds.
Question
The strategy best suited to exploit the second analyst's expected changes to the current fixed-income environment is to:
A extend duration and construct a bullet portfolio.
B extend duration and construct a barbell portfolio.
C keep duration constant and construct a barbell portfolio.
B is correct.
从题目中可以看出，牛市，利率会下降，并且长期下降幅度更大。那为什么要选择构建barbell portfolio？它和bullet portfolio 应该如何选择？
