Planetary boundary layer (PBL) Planetary boundary layer (PBL), also called atmospheric boundary layer, the region of the lower troposphere where Earthâs surface strongly influences temperature, moisture, and wind through the turbulent transfer of air mass.
Portfolio optimization tools are useful to assist planners, advisers, and clients in ways to conceptualize the asset allocation problem. But, they should not be relied upon as the primary tool for structuring an investment portfolio.
Ladder Strategy. An investment strategy in which one invests in several securities with different maturities. When the first one matures, the yield may or may not be used to buy another security. It is used most often with bonds and certificates of deposit. Laddering protects the investor from interest rate risk by locking in interest rates at once. Suppose one does not use laddering: one may invest $30,000 in a five-year bond with a 4% coupon. When the bond matures, prevailing interest rates may have dropped to 2%, making it impossible to achieve the same profit reinvesting in the same type of bond.