bboo

By definition: Portable alpha - alpha available to be added to a variety of systematic risk exposures.

Long only investors have exposure to both beta (makret return) and alpha (mgr skill)

Alpha beta separation - investor gains an exposure to beta (zero alpha) thru a low cost index fund, and add an alpha thru a long short market neutral portolio (assuming zero beta although but not necessary). Alternatively the investor may just want to employ a market neutral long short manager to generate the alpha which is an example of portable alpha i.e. alpha available to be added to a variety of systematic risk exposures.