I am creating an algorithm where all alpha comes from short leg of the portfolio. Why do I need to keep a set of long stocks and waste away in transaction cost when I can just buy SPY for long exposure.
Any kind of attempt to replicate SPY burns too much in transaction cost and is not worth it. Uniform allocation to long leg is one way to go but it introduces unnecessary/unwanted tracking error with no guaranteed upside performance.
Is there any cheap way to replicate SPY?