Yes thats right Zpana, Portable alpha is nothing but just same as equitizing Long Short strategy, the only difference being. The Beta exposure is generally in a Efficient market and Alpha exposure is done through long-short strategy in a lesser efficient market.
The reason being the chances of finding Alpha in an efficient market is very costly. So get Beta exposure in that market and Alpha exposure in another lesser informationally efficient market.
You can gain on both sides so if you are unfavorable about a stock u can short it. If you are long only you just cannot hold the stock if you do not like it. Hence it has negative weight in your portfolio compared to teh benchmark.
You can transfer or move your alpha around to desired beta exposures. portable alpha.
You can also have short extension strategies where you use the proceeds from the short sale to invest (100+x)% on the long side.
I’d point out that you are all speaking of long/short as if it is market neutral (beta of zero). This is not always the case as many long/short strategies have a positive beta, long bias, positive net exposure, etc.
Market-neutral strategies have more of a portable alpha because the underlying markets need not be the same, e.g. execute market-neutral in equity and earn alpha in fixed income.
Long-short is restricted to the same market to earn alpha - long positive alpha stocks and short negative ones.If you try to equitize, you may get unwanted long exposure for stocks that you have shorted (since beta implies buying the whole market.)
Think 120/20 strategy (short negative alphas for a total of 20% of your portfolio + invests original cash and proceeds from shorts in long-alpha ideas for a total long exposure of 120% of the initial portfolio value)